[Warner306]

Both players decode with LAV Video. Compare your settings. The two should produce identical results.

What kind of CPU do you have? This would be news to me that new CPUs are capable of software decoding. Is this a 1:1 rip, or is it compressed? No one that I've come across has said that a HEVC decoder is not necessary. On the contrary, everyone has said this is a basic requirement for 4K UHD playback. 

My CPU is a 4690k overclocked to 4.7ghz. I believe this cpu supports HEVC decoding, it's just really rough compared to GPU decoding, but I'm a novice so don't quote me....

Here's Coco running perfectly smooth with MPC-HC: https://imgur.com/a/DR5eZ Same exact MadVR profile that DSP is using. Only difference is I can leave it running indefinitely and no stuttering will happen. Even during 'complex' scenes, it will always playback perfectly. As do all my other 1:1 4K remuxes.

Something in DSP is making the decoder drop to 0/1. My only suspicion is XySubFilter which doesn't show in taskbar with MPC-HC, but it DOES with DSP.   

 Looks fine to me. Your CPU may be able to decode HEVC at 23.976. It is as fast as it gets. Good to know. I still think it would choke at higher frame rates, though. Any CPU can software decode. It is just a matter of being fast enough.

I assume hardware acceleration is set to none in DSPlayer? If so, this looks like a bug in DSPlayer. I don't know how to fix it for you. You may have to launch an external player from DSPlayer for your UHD remuxes until you get your new graphics card.

That CPU is screaming fast.