[SOLVED] Trying to understand 5800x/5600x benchmark results

[bbsmitz]

Hi All,

I'm currently completing my first new build in a long while (link to pcpartpicker list). It'll be a general purpose machine, for both work and gaming. I had essentially settled on the 5950x as my processor, but I also am a bit of a flight sim nut, and this recent review seems to show that the 5800x/5600x strongly out perform the 5900/5950 when PBO is turned on. The difference isn't small either; 10%+. Such a large gap doesn't really show up on any of the other benchmarks. So a does anyone have any ideas why the gap manifests so strongly for MSFS and not for other benchmarks? I'd have said it was the fact that all the cores are on a single die, but that's not the case for the 5600x which more or less matches the 5800x. Do the 5600x and 5800x just OC better than the higher core models? Any ideas on whether MSFS moving to DX12 might close this gap a little, or is >8 cores not really going to matter, even with that change. Thanks for reading guys.

Best,

-bbsmitz

 

[rgd1101]

msfs is heavy cpu thread bound.
less core, less heat

 

[bbsmitz]

Well the 5800x has all 8 cores on the same die, so shouldn't that make it run hotter locally than say a 5900x which only has 6 per die?

 

[rgd1101]

total core. not just how many core in a die.
the cpu is not that big.

 

[bbsmitz]

So essentially it's a cooling bottle neck you think?

 

[rgd1101]

what do you mean bottleneck? you can have more cores with lower max freq or few cores with higher max freq

or you can go crazy with this
https://www.tomshardware.com/news/overclocking-5950x-to-6-ghz-16-cores

 

[drea.drechsler]

Noting this is under PBO which still uses the processor's boosting algorithm.

The algorithm opportunisticaly boosts processor cores based on thermal margins (which has already been discussed) but also based on motherboard power margins. It only makes sense the power margins will be more limiting for a 16 core/32 thread processor than a 6 core/12 thread processor even when relaxed by using PBO.

It seems possible that better tuning of the PBO settings for the 5950X could help assuming they didn't spend much time on that. That might improve it's boosting potential which could have more impact on light threaded game (like MSFS20) performances when it's not otherwise thermally limited.

I also note that PBO settings for 3000 series processors had very counter-intuitive behavior...often times looking like it's flat out buggy. That may be true with settings for the 5000 series so it could take some time to find the right setting range that lets the processor boost properly without running into arbitrary power limits.