[rorylawson]

Hi,

If I was to install a 64-bit version of Ubuntu on machine due to having more than 3.5GB of RAM, could I run 32-bit XBMC on top without any problems?

Am I right in thinking that having a 64-bit OS wouldn't make any difference because XBMC runs in 32-bit mode and wont be able to use the RAM over 3.5GB? So until XBMC is ported to 64-bit, it can not take advantage of the higher RAM?

Cheers,
Rory

[vikjon0]

A bigger problem is that xbmc does not use that much memory anyway. Some operations are quicker in 64bit as far as I understand but I have not seen any such arguments for xbmc.

[rorylawson]

I guess I was thinking more about the higher end skins like Aeon which do load a lot of heavy graphics...just wondered if having a 64-bit OS would improve performance much?

Cheers,
Rory

[vikjon0]

It may be quicker in true 64bit but not becuase of the extra memory I dont think. You should also note that that 64bit will require MORE memory. In theory this could make your system run slower.

[vikjon0]

Some 64-bit programs, such as encoders, decoders and encryption software, can benefit greatly from 64-bit registers, while the performance of other programs, such as 3D graphics-oriented ones, remains unaffected when switching from a 32-bit to a 64-bit environment. It is unusual for a 64-bit program to perform worse than its 32-bit equivalent; this usually only happens due to a bug.[21]
Some 64-bit architectures, such as x86-64, support more general-purpose registers than their 32-bit counterparts (although this is not due specifically to the word length). This leads to a significant speed increase for tight loops since the processor does not have to fetch data from the cache or main memory if the data can fit in the available registers.

If we can trust the old wiki it sounds like 64 WOULD be quicker assuming you use a 64bit ffmpeg.

[bobo1on1]

If you install a 32 bit version of ubuntu, you automatically get a pae enabled kernel, so you can use 64 gb of ram max.
However you're still limited to 4 gb per process.

Using a 64 bit ubuntu with a 64 bit xbmc should work ok.

[routehero]

I have ubuntu x64 and frequently build xbmc from git repository.

I've got about 2TB of media, the largest file in ~/.xbmc/userdata/Database/ is 3MB, and I'm using refocus skin.

xbmc.bin has VSZ of about 720MB on my system, and my memory usage is relatively flat.

I don't think you will perceive a difference in performance in x64. Unless you have a very memory hungry JVM also running on the same system, you probably won't notice the lack of 64-bit.

[Balthazaar]

I'm running 64 bit Ubuntu 11.04 with xbmc built from git. I agree with routehero, I notice no difference in performance from the 32 bit version of the same build I run on Ubuntu 11.04 32 bit.