[DrVlikhell]

The downside is, I think the Lenovo BIOS has some wattage limits baked in that I can't alter. In most loads it runs at 47w, but it won't do it's 58w 'Short Turbo' speed, it's also running slightly below it's max turbos, I was able to hit 3.0ghz sustained with some undervolting, 2.8ghz without undervolting. It also seems to run SLOWER under some loads, where I can get 3.0ghz in Cinebench R15, it runs at 2.45 and a lower TDP while running R20. AVX2 power consumption thing maybe? So yes, in the restrictive Lenovo box, it's an amazing upgrade but it's not running as optimally as it would on a desktop board with user configurable settings.

I registered on this forum just to ask you about your system and experiences with it and different CPUs, TDP, throttling, etc. I have three of these Lenovo Tiny systems, one M93p and two M73's. If you're not familiar with the M73 version, it's almost identical to the M93p except it has an H81 chipset instead of the Q87 in the M93p, and some of the USB ports are only USB 2.0, otherwise they're identical. I currently have an i7 4770S in the M73 and while it boots up and runs fine, I've been concerned about it drawing too much power through the motherboard and eventually causing the board to fail. The 4770S is a 65W TDP CPU while the system was only designed for a 45W TDP CPU, and while TDP refers to maximum heat production/dissipation, in order to produce more heat you have to draw more power, which is my main concern.

Then I read this post where you mentioned above about there possibly being a power limit in the BIOS. I also happened to find your post on Reddit (it has the same keywords) where you said you had an i5 4590 (which has double the TDP!) in your M93 and the system engaged current throttling. How long did you have the 4590 in it and could you elaborate a bit about how and when you observed the current throttling with that CPU and your current one? Also, you mentioned that you managed to undervolt your current CPU. How did you do that? I didn't see any voltage settings in the BIOS on any of my Lenovo systems. 

I'm not concerned about heat because I'll be using that particular M73 for a Plex server and it should rarely run at 100% CPU usage, and never long enough to completely overwhelm the little CPU cooler. However, I'm concerned about potentially damaging the motherboard by drawing too much power through it, even if it's for only short periods of time. I have a 90 watt power adapter and my wall power meter says it never comes close to using all of that so I'm good on that front. In the Windows power settings I've set the "Maximum processor state" to 90% in hopes of limiting power draw there as well. If I remember correctly, in CPUID HWMonitor, under Powers:Package it never goes above roughly 45W, but I don't know if that's an accurate metric for actual current draw.

My goal isn't to have an extremely fast Tiny system for my Plex server, but just to have something a bit stronger than a dual core CPU in it without spending a bunch of money, and I happened to have the i7 4770S available. If using the 4770S isn't viable or safe, I'll probably just go with a cheap dual core T series CPU. Any insight you have with this would be greatly appreciated.

[DJ_Izumi]

I registered on this forum just to ask you about your system and experiences with it and different CPUs, TDP, throttling, etc. I have three of these Lenovo Tiny systems, one M93p and two M73's. If you're not familiar with the M73 version, it's almost identical to the M93p except it has an H81 chipset instead of the Q87 in the M93p, and some of the USB ports are only USB 2.0, otherwise they're identical. I currently have an i7 4770S in the M73 and while it boots up and runs fine, I've been concerned about it drawing too much power through the motherboard and eventually causing the board to fail. The 4770S is a 65W TDP CPU while the system was only designed for a 45W TDP CPU, and while TDP refers to maximum heat production/dissipation, in order to produce more heat you have to draw more power, which is my main concern.

Then I read this post where you mentioned above about there possibly being a power limit in the BIOS. I also happened to find your post on Reddit (it has the same keywords) where you said you had an i5 4590 (which has double the TDP!) in your M93 and the system engaged current throttling. How long did you have the 4590 in it and could you elaborate a bit about how and when you observed the current throttling with that CPU and your current one? Also, you mentioned that you managed to undervolt your current CPU. How did you do that? I didn't see any voltage settings in the BIOS on any of my Lenovo systems. 

I'm not concerned about heat because I'll be using that particular M73 for a Plex server and it should rarely run at 100% CPU usage, and never long enough to completely overwhelm the little CPU cooler. However, I'm concerned about potentially damaging the motherboard by drawing too much power through it, even if it's for only short periods of time. I have a 90 watt power adapter and my wall power meter says it never comes close to using all of that so I'm good on that front. In the Windows power settings I've set the "Maximum processor state" to 90% in hopes of limiting power draw there as well. If I remember correctly, in CPUID HWMonitor, under Powersackage it never goes above roughly 45W, but I don't know if that's an accurate metric for actual current draw.

My goal isn't to have an extremely fast Tiny system for my Plex server, but just to have something a bit stronger than a dual core CPU in it without spending a bunch of money, and I happened to have the i7 4770S available. If using the 4770S isn't viable or safe, I'll probably just go with a cheap dual core T series CPU. Any insight you have with this would be greatly appreciated.

Okay, so, before I say anything, keep in mind that I am a Rando on the internet and a single point of data. You do everything at your own risk. Anyway, the current throtteling seems to be universal. I can also face current throtteling on the i7 4750HQ though not as bad. I used Intel XTU to carefully undervolt the chip as much as I could to get more performance out of it. Since it's operating under a strict 45w budget, inching down it's voltages in some areas let me get some more performance out of that budget. Obviously the mobile i7 4750HQ can get much better performance per watt than the i5 4590. (It even out performs the i5 4590 when installed in a B85 Desktop board. :O) That said I only tested the fat i5 4590 for about an hour. I suggest you install Intel XTU and do your own testing and observations. But yeah, I don't THINK damage is a concern because the system itself will literally just go 'No, you get 45 watts. No more. I don't care if both CPU and GPU are running, you two can compete for watts.' I can't even find away to override it. That said, I briefly tested a 3770K in an M92P Tiny and that did not current throttle at all. It overheated and shut down in Cinebench. Do don't try it on an M92P Tiny.

I did upgrade from a 65w brick to a 90w brick though I found the use cases of exceeding 65w to be rare. I had to run a CPU and GPU intensive benchmark, spin the optical drive at full speed, and write 1gbps of data to the SSD, all concurrently, to get a bit over 75w. I don't think it's POSSIBLE to draw more power than that unless I somehow try to max out the USB bus power on every port. So 65w could have been a liability in some cases, I'm not worried with a 90w brick.

So I THINK you'd be fine using a 4770S, but it might under perform vs a desktop CPU and you should observe it with Intel XTU and a Kill-A-Watt to be sure. That said, these hacked up Chinese mobile CPUs seem MORE expensive now and I'd not suggest using one of those unless you were bored and had a lot of overtime money like I did. Nothing about the M93P Tiny really is a GOOD idea, it was just fun to do. I could have gotten some SkyLake thin client doing 4K HEVC no problem after all.

[DrVlikhell]

Okay, so, before I say anything, keep in mind that I am a Rando on the internet and a single point of data. You do everything at your own risk. Anyway, the current throtteling seems to be universal. I can also face current throtteling on the i7 4750HQ though not as bad. I used Intel XTU to carefully undervolt the chip as much as I could to get more performance out of it. Since it's operating under a strict 45w budget, inching down it's voltages in some areas let me get some more performance out of that budget. Obviously the mobile i7 4750HQ can get much better performance per watt than the i5 4590. (It even out performs the i5 4590 when installed in a B85 Desktop board. :O) That said I only tested the fat i5 4590 for about an hour. I suggest you install Intel XTU and do your own testing and observations. But yeah, I don't THINK damage is a concern because the system itself will literally just go 'No, you get 45 watts. No more. I don't care if both CPU and GPU are running, you two can compete for watts.' I can't even find away to override it. That said, I briefly tested a 3770K in an M92P Tiny and that did not current throttle at all. It overheated and shut down in Cinebench. Do don't try it on an M92P Tiny.

I did upgrade from a 65w brick to a 90w brick though I found the use cases of exceeding 65w to be rare. I had to run a CPU and GPU intensive benchmark, spin the optical drive at full speed, and write 1gbps of data to the SSD, all concurrently, to get a bit over 75w. I don't think it's POSSIBLE to draw more power than that unless I somehow try to max out the USB bus power on every port. So 65w could have been a liability in some cases, I'm not worried with a 90w brick.

So I THINK you'd be fine using a 4770S, but it might under perform vs a desktop CPU and you should observe it with Intel XTU and a Kill-A-Watt to be sure. That said, these hacked up Chinese mobile CPUs seem MORE expensive now and I'd not suggest using one of those unless you were bored and had a lot of overtime money like I did. Nothing about the M93P Tiny really is a GOOD idea, it was just fun to do. I could have gotten some SkyLake thin client doing 4K HEVC no problem after all.

Hey, thanks for the reply! My main concern is not frying whatever voltage/current regulators that the motherboard is using to keep the CPU from using more than 45 watts. I know very little about current and voltage regulators, but I do know that you can over heat them and blow them up... sometimes. I also know of at least one person (likely many more too) that used a regular 54W i3 in their M93 and it ran fine for years. They have recently upgraded to a Xeon E3-1275L V3 and it's still running fine.

If I don't use the 4770S there are a few 4 core 35/45W CPUs that would fit pretty nicely, but that would mean spending money, and I'm at the opposite end of the spectrum from you, trying to spend as little as possible. So far the only money spent was on the bare M73 chassis itself and the SSD. The CPU was pulled from another tower (that got downgraded back to a spare dual core), the ram is from an old failed laptop, the power brick is a spare for one of my current laptops. Add in the adapter to use an older round plug power brick and the DP to HDMI adapter and I'm at about $37 all in. A 4590T would be about that much itself, but it would definitely stay within the power envelope.

It's interesting that your CPU and iGPU fight for power when the whole package is rated at 47W while the Tiny can definitely deliver 45W, and your CPU is even undervolted. You'd think that you should be able to run at near 100% performance. How can you tell when your CPU is being throttled? I don't notice any indications except that the 4770S performs much lower in benchmarks than it did in a full ATX system, and of course I can watch the CPU package power in HWMonitor. But otherwise I don't notice any signs. 

I'll look into trying Intel XTU for undervolting, however I'm not looking for extra performance in this case, the 4770S is overkill as it is. I just want to keep things safe. I might turn down the "Maximum processor state" in Windows power management a little further to 80% just to be on the safe side as well. Maybe I'll see how far I have to turn it down before it no longer pulls ~45W according to HWMonitor.

Just as I was thinking about the undervolting process it occurred to me that maybe something similar is how it limits CPU wattage, by limiting VID... A quick test on this system shows that VID varies between .87 and 1.27 depending on load. I'll have to do some testing on the Tiny and see what it does. If so, then there should be no worries at all since those voltage regulators are meant to do that.

Thanks again for your input. I'm a big fan of these Tiny systems and it's great to see one that's maxed out like yours. I'd say post some pics of it... but they all look exactly the same!

[DJ_Izumi]

Hey, thanks for the reply! My main concern is not frying whatever voltage/current regulators that the motherboard is using to keep the CPU from using more than 45 watts. I know very little about current and voltage regulators, but I do know that you can over heat them and blow them up... sometimes. I also know of at least one person (likely many more too) that used a regular 54W i3 in their M93 and it ran fine for years. They have recently upgraded to a Xeon E3-1275L V3 and it's still running fine.

It's interesting that your CPU and iGPU fight for power when the whole package is rated at 47W while the Tiny can definitely deliver 45W, and your CPU is even undervolted. You'd think that you should be able to run at near 100% performance. How can you tell when your CPU is being throttled? I don't notice any indications except that the 4770S performs much lower in benchmarks than it did in a full ATX system, and of course I can watch the CPU package power in HWMonitor. But otherwise I don't notice any signs.

 I get your concerns. For example, I'm pretty sure I recently killed an HP T730 thin client. This is a larger unit that has a PCIE slot inside for low profile, single slot cards. So I fixed a low profile Radeon RX 460 into. Yeah it did NOT like having a 50w GPU inside it. One 3D Gaming engaged it would 'blink out' and in testing, trying to bring down the TDP, I think I killed both the T730 itself and a 4GB stick of DDR3. =X

However in the case of intel CPUs, I'm pretty sure the TDP limit is controlled by the system and chip itself. It's not that the system can't PROVIDE more power, it's that it disallows TAKING more power. So the CPU is told '45w is what you get, you may not take more'. It's akin to Radeon Wattman or other functions where the system sets a limit and the hardware thus won't exceed that limit.

I've also read some threads on these Chinese hacked up mobile chips in desktop sockets that show that in a desktop overclocking board, where the TDP limits can be disabled, they run way faster and can even overclock amazingly. Basically a highly efficient mobile chip running with no restrictions showing just how far it can go.

[idyllik]

just to add another sample to the pile
recently upgraded my m93p tiny with an i7 4870hq and have noticed that cpu ia activity is limited to 35w package power no matter what I set in xtu
on the other hand gt power draw will happily draw whatever power limit you set until it thermally throttles
seems the only way to get the cpu frequency higher during all core system loads is to undervolt it I.e. cinebench r20 will run at 24x multiplier at 0 offset, with a -125mv offset it will run at 27x

i've modified my top chassis to expose the little section above the fan and will happy cool a 50w sustained package load to around 50-55c over ambient(got a good 10c drop in temperatures from the mod), would be great to get that extra 15w of performance

[DrVlikhell]

I had also thought about cutting a hole over the CPU fan to let cool air in directly, maybe even with a 3d printed vent/scoop, but I like the aesthetics of the flat top. Mine is also rarely under enough load to increase the thermals enough to worry, so I don't think it'd help much in my case.

I've been reading up a bit on XTU and more on Throttlestop and it does indeed seem like the CPU is told by the motherboard how much power it's allowed to use instead of flat out limiting the current available to it. That makes sense because if you limit the current available and the CPU wants more it would probably cause instabilities. Unfortunately I haven't found anything solid from Intel about it. But if that's true then it negates my worries about burning up something on the board by running higher TDP CPU. The board effectively makes any CPU a T series CPU by telling it to hold back on the current draw. I guess I'll just let it run as is and hope nothing bad happens.

[idyllik]

the thing to note is the 35w limit I mentioned is all core cpu loads only I.e. runnning aida64 stress fpu
on gpu loads it will suck whatever limit you give it I.e. running furmark, hwinfo reports the package power at 60w

[DrVlikhell]

the thing to note is the 35w limit I mentioned is all core cpu loads only I.e. runnning aida64 stress fpu
on gpu loads it will suck whatever limit you give it I.e. running furmark, hwinfo reports the package power at 60w

Oh, I see, so the GPU isn't current limited the same way the CPU is? That's ok for my setup since I'll be using it as a server and the GPU won't see much duty unless Plex decides to use it for transcoding (not likely). Thanks for the info.

[idyllik]

posting a correction here, the first 4870hq I had seemed to be faulty(produced whea errors) and the second replacement for that has died with what appears to be a bad imc(post errors are for no memory) so I don't know whether that affected the initial results with an artificial cap of 35w

popped in an i5 4570 from my larger m93p and it appears it WILL in fact draw much more power if it wants to
currently running the 4570 with a -100mv offset for core, cache, and igpu with a limit of 43.750watts on the turbo boost power max(disabled the turbo boost short power max) and during aida64's fpu test the package tdp will sit around the 54w mark with the ia tdp at around 47watts
ran occt with avx2 and it'll limit itself for a while but will somehow unlock the turbo boost power max limit and will continue to draw a bunch of power(noticed this when the fan started making a bunch of noise at 5000+rpm, have the unit plugged into an external current reader which was showing 92w before I pulled out of the test)

continuing to investigate this

[idyllik]

following up this, seems the problem with avx loads being uncapped was a problem with intel xtu and have since switched to throttlestop
have limited pp0, pl1, and pl2 to 52w which appears to have hardlocked everything to 52w whether it's cpu load, avx loads, or gpu loads
have also switched out the i5 4570 in favour of an i7 4790s
with a 52w cpu load, 21-22c ambient, I'm seeing package temps of around 55c above ambient with an average fan speed of around 3100rpm
before delidding and liquid metal application, I was seeing load temps of around 64c above ambient with an average fan speed of 3900rpm

shame about the 4870hq's dying, the iris pro 5200 had almost twice the performance

[DJ_Izumi]

I'm not shocked by the 4870HQ, these are chips hacked up by a third party into LGA1150.  These should NOT exist.  It's why I bought mine on eBay, they have great consumer sided protections.  If they sent me jank, I'd get a refund.

[DrVlikhell]

following up this, seems the problem with avx loads being uncapped was a problem with intel xtu and have since switched to throttlestop
have limited pp0, pl1, and pl2 to 52w which appears to have hardlocked everything to 52w whether it's cpu load, avx loads, or gpu loads
have also switched out the i5 4570 in favour of an i7 4790s
with a 52w cpu load, 21-22c ambient, I'm seeing package temps of around 55c above ambient with an average fan speed of around 3100rpm
before delidding and liquid metal application, I was seeing load temps of around 64c above ambient with an average fan speed of 3900rpm

shame about the 4870hq's dying, the iris pro 5200 had almost twice the performance

Hey, thanks for the followup. Sucks that the 4870 didn't work out. There are a few other cpus with the iris pro 5200 gpu, but I haven't seen any on the market. 

In Throttlestop, where did you limit pl1 and pl2? In the "Turbo Power Limits" menu I only see pp0. Any chance you could post a screen shot of your settings? I just moved my 4770s from my M73 to a recently acquired M93p Tiny, so now your setup and mine are nearly identical. I was testing with Prime95 and seeing an initial spike up around 90 watts at the wall, which can't be good for the little systems lifespan. 

Unrelated, I picked up an M83 Tiny last week because it was dirt cheap. Now I have an M73, M83, and two M93p. Do I have a Tiny problem?

[idyllik]

turbo boost long power max = pl1
turbo boost short power max = pl2

I just set both to 52(wanted to go direct die but the stock cooler made contact with the core but did not have enough pressure to push the cpu into the socket), ticked clamp on both and maxed out the turbo time limit

a few tiny's would be nice but I just don't have enough things to do with them i've got a 500gb ssd in there along with another de-shelled sandisk 256gb ssd hooked up via usb3 with a cable out the back for more storage(already had the parts lying around, did the same thing to an asus chromebox which turned out okay)

edit; wanted to add since I also dual-boot macos with the m93p tiny, once you feel out the settings you want to use for undervolting and setting pl1/2 you can use voltageshift to apply the same settings in macos too

[degarr]

The downside is, I think the Lenovo BIOS has some wattage limits baked in that I can't alter. In most loads it runs at 47w, but it won't do it's 58w 'Short Turbo' speed, it's also running slightly below it's max turbos, I was able to hit 3.0ghz sustained with some undervolting, 2.8ghz without undervolting. It also seems to run SLOWER under some loads, where I can get 3.0ghz in Cinebench R15, it runs at 2.45 and a lower TDP while running R20. AVX2 power consumption thing maybe? So yes, in the restrictive Lenovo box, it's an amazing upgrade but it's not running as optimally as it would on a desktop board with user configurable settings.

I registered on this forum just to ask you about your system and experiences with it and different CPUs, TDP, throttling, etc. I have three of these Lenovo Tiny systems, one M93p and two M73's. If you're not familiar with the M73 version, it's almost identical to the M93p except it has an H81 chipset instead of the Q87 in the M93p, and some of the USB ports are only USB 2.0, otherwise they're identical. I currently have an i7 4770S in the M73 and while it boots up and runs fine, I've been concerned about it drawing too much power through the motherboard and eventually causing the board to fail. The 4770S is a 65W TDP CPU while the system was only designed for a 45W TDP CPU, and while TDP refers to maximum heat production/dissipation, in order to produce more heat you have to draw more power, which is my main concern.

Then I read this post where you mentioned above about there possibly being a power limit in the BIOS. I also happened to find your post on Reddit (it has the same keywords) where you said you had an i5 4590 (which has double the TDP!) in your M93 and the system engaged current throttling. How long did you have the 4590 in it and could you elaborate a bit about how and when you observed the current throttling with that CPU and your current one? Also, you mentioned that you managed to undervolt your current CPU. How did you do that? I didn't see any voltage settings in the BIOS on any of my Lenovo systems. 

I'm not concerned about heat because I'll be using that particular M73 for a Plex server and it should rarely run at 100% CPU usage, and never long enough to completely overwhelm the little CPU cooler. However, I'm concerned about potentially damaging the motherboard by drawing too much power through it, even if it's for only short periods of time. I have a 90 watt power adapter and my wall power meter says it never comes close to using all of that so I'm good on that front. In the Windows power settings I've set the "Maximum processor state" to 90% in hopes of limiting power draw there as well. If I remember correctly, in CPUID HWMonitor, under Powersackage it never goes above roughly 45W, but I don't know if that's an accurate metric for actual current draw.

My goal isn't to have an extremely fast Tiny system for my Plex server, but just to have something a bit stronger than a dual core CPU in it without spending a bunch of money, and I happened to have the i7 4770S available. If using the 4770S isn't viable or safe, I'll probably just go with a cheap dual core T series CPU. Any insight you have with this would be greatly appreciated.

DrVlikhell you wouldn't be making a HA Proxmox cluster out of 3 of them would you? as that is what I am doing

[DrVlikhell]

The downside is, I think the Lenovo BIOS has some wattage limits baked in that I can't alter. In most loads it runs at 47w, but it won't do it's 58w 'Short Turbo' speed, it's also running slightly below it's max turbos, I was able to hit 3.0ghz sustained with some undervolting, 2.8ghz without undervolting. It also seems to run SLOWER under some loads, where I can get 3.0ghz in Cinebench R15, it runs at 2.45 and a lower TDP while running R20. AVX2 power consumption thing maybe? So yes, in the restrictive Lenovo box, it's an amazing upgrade but it's not running as optimally as it would on a desktop board with user configurable settings.

I registered on this forum just to ask you about your system and experiences with it and different CPUs, TDP, throttling, etc. I have three of these Lenovo Tiny systems, one M93p and two M73's. If you're not familiar with the M73 version, it's almost identical to the M93p except it has an H81 chipset instead of the Q87 in the M93p, and some of the USB ports are only USB 2.0, otherwise they're identical. I currently have an i7 4770S in the M73 and while it boots up and runs fine, I've been concerned about it drawing too much power through the motherboard and eventually causing the board to fail. The 4770S is a 65W TDP CPU while the system was only designed for a 45W TDP CPU, and while TDP refers to maximum heat production/dissipation, in order to produce more heat you have to draw more power, which is my main concern.

Then I read this post where you mentioned above about there possibly being a power limit in the BIOS. I also happened to find your post on Reddit (it has the same keywords) where you said you had an i5 4590 (which has double the TDP!) in your M93 and the system engaged current throttling. How long did you have the 4590 in it and could you elaborate a bit about how and when you observed the current throttling with that CPU and your current one? Also, you mentioned that you managed to undervolt your current CPU. How did you do that? I didn't see any voltage settings in the BIOS on any of my Lenovo systems. 

I'm not concerned about heat because I'll be using that particular M73 for a Plex server and it should rarely run at 100% CPU usage, and never long enough to completely overwhelm the little CPU cooler. However, I'm concerned about potentially damaging the motherboard by drawing too much power through it, even if it's for only short periods of time. I have a 90 watt power adapter and my wall power meter says it never comes close to using all of that so I'm good on that front. In the Windows power settings I've set the "Maximum processor state" to 90% in hopes of limiting power draw there as well. If I remember correctly, in CPUID HWMonitor, under Powersackage it never goes above roughly 45W, but I don't know if that's an accurate metric for actual current draw.

My goal isn't to have an extremely fast Tiny system for my Plex server, but just to have something a bit stronger than a dual core CPU in it without spending a bunch of money, and I happened to have the i7 4770S available. If using the 4770S isn't viable or safe, I'll probably just go with a cheap dual core T series CPU. Any insight you have with this would be greatly appreciated.

DrVlikhell you wouldn't be making a HA Proxmox cluster out of 3 of them would you? as that is what I am doing

Nope, mine are employed mostly just for media. One as a htpc and one as a Plex/VPN/Pihole server. The other two don't have a purpose yet... still trying to figure out what to do with them. HA clusters are pretty damn cool though. Mad props for setting that up.

turbo boost long power max = pl1
turbo boost short power max = pl2

I just set both to 52(wanted to go direct die but the stock cooler made contact with the core but did not have enough pressure to push the cpu into the socket), ticked clamp on both and maxed out the turbo time limit

a few tiny's would be nice but I just don't have enough things to do with them i've got a 500gb ssd in there along with another de-shelled sandisk 256gb ssd hooked up via usb3 with a cable out the back for more storage(already had the parts lying around, did the same thing to an asus chromebox which turned out okay)

edit; wanted to add since I also dual-boot macos with the m93p tiny, once you feel out the settings you want to use for undervolting and setting pl1/2 you can use voltageshift to apply the same settings in macos too

I tried doing that with mine but with lower numbers, and it seems to just ignore them and go higher than the limit that I set. Maybe Throttlestop only works to increase limits above stock and doesn't work to lower it below stock.