Speedstep & PCSX2

[Air]

Additionally, the problem is most pronounced on games that have especially high load on one thread, but low load on another. In PCSX2 there are two threads doing most of the work: the EE thread and the GS thread. If the GS thread is having an especially low workload as compared to the EE thread, SpeedStep will be much more likely to throttle the CPU's overall speed.

Now here's the kicker. The work load of the GS is directly proportional to the speed at which the EE can feed it geometry and texture data. When Speedstep starts to throttle the CPU, the EE thread load stays near 90-99%, but its effectively running slower and thus feeds the GS less work, so the GS thread also stays around whatever low workload it has (perhaps 15-40%, for example). The Speedstep sees that only 60-70% of the total CPU resources are in use, and throttles down even more. Rinse and repeat.

This is why PCSX2 "looks" like its adjusting its workload to the reduced CPU speed. Its still trying to work as fast as it possibly can, but the GS thread is going to look ever more increasingly "idle" to the dumb ***** CPU so long as it keeps throttling the EE's speed.

It is very much a design flaw in Speedstep that I think has been mostly remedied in the i5/i7 chips, thanks to their 1/2 thread turbo boost feature.

[nosisab Ken Keleh]

Air, very insightful post, sadly it landed (crashed?) my beliefs in an easy solution

[rama]

Disable speedstep, lol.

[nosisab Ken Keleh]

Now I feel stupid lol that's a SOLUTION in all capital glory, for some reason I was tied to keeping it and get around.

Jokes apart, that's a lesson to take from relying in automatic solutions being good in all circumstances, profiles are there to allow quick changes between configurations...

[Mika]

Well, I think disabling Speedstep seems like too much (since I think it's really useful), moving from Power Saver profile to a Balanced profile solved the super aggressive throttling problem I was seeing. Even though the I edited the profiles to appear identical, there's something there that users can't configure.

But to each their own.

[nosisab Ken Keleh]

better would be to keep the profiles as they are and toggling between them when starting and finishing the game session

[Mika]

Nah. PC micromanaging is too much trouble.

[naoan]

Actually there's this little program called process monitor (shareware but functional trial with some limitation) that can be configured to change power plan to high when specific app is launched. Handy but the shareware status may put off some, I still can't find the free one with similar function...