CPU Turbo

[MakeeLearn]

Intel i7

I posted this in tm.asp?m=3858059. Since this covers more than just laptops I decided to post a new thread.

I went into the BIOS and disabled the cpu performance turbo and now my computer runs WitPAE quieter and cooler. It also seems to be quicker/smoother on the interface response.
WitPAE now is like a different game.

[wdolson]

The interface turbo setting probably does something to boost the multithreading of the video processing. The DirectX calls in AE step on themselves with multiple processors. Many of the calls launch a new process to do a task and then wait for the task to finish before continuing. On a single core processor this works fine because the new process can't start until the old one is done. On a multi-core processor there is a risk the new process will be done before the starting process is ready and the starting process will sit there waiting for the spawned process to complete not realizing it's already done. After the time-out, it launches again only to find out it's done.

That's why we have the various single CPU command line flags. This turns off various multi-core features in the processor for AE only and avoids this fumbling. The problems can crop up in the video processing or just the main processor itself, or it could be both. Hence the multiple flags.

When you turned off the turbo boost on the video, you probably turned off multi-core processing on the video for all programs, which improved AE.

Bill

[MakeeLearn]

I was already running with the various command line switches and disabling the turbo even improved that.

[Chris21wen]

ORIGINAL: MakeeLearn

I was already running with the various command line switches and disabling the turbo even improved that.

I might do but it has one drawback, it will also affect everything else.

[Rafid]

ORIGINAL: MakeeLearn
Intel i7

I went into the BIOS and disabled the cpu performance turbo and now my computer runs WitPAE quieter and cooler. It also seems to be quicker/smoother on the interface response.
WitPAE now is like a different game.

WITPAE usually uses only one core, but then to 100%. The turbo mode will in these scenarios lift the clock speed of that one core by about 400 MHz (amount depends on exact model of i7). Upping the core speed increases the power draw and hence temperature and noise. This increase is very non-linear towards the end of CPUs capabilities, meaning that clocking from 4 GHz to 4.4 GHz (+10 %) can result in an increase in power draw of 25 % or more. So far everything seems logical, but I struggle to see why the game would run smoother with a lower clock speed (turbo off). Maybe Bill's answer gives a hint and the turbo clock speed is used for opening more threads (or some other type of overhead) that end up spending more time blocking each other than doing anything useful?

More at the bottom of this is the fact that AE has no business using 100% of a core constantly! Maybe during turn resolution, but not while waiting for user input. My best guess is that there is some kind of loop in the engine that constantly asks "Was a button pressed? Was a button pressed? Was a button pressed?" at the maximum speed possible (or constantly repaints the screen even if nothing moves or similar). Additional CPU power is instantly used for more useless questions. At some point they might even block each other and make the game run less smooth. In the very old days it was not unusual to refresh an engine as quickly as possible. Any half modern UI code however will have a maximum internal refresh rate (not to be confused with the refresh rate of the screen) that would have the CPU load hover way below 100% during the order phase. It's perhaps a liability carried over from the engine's origins in the UV days.

@MakeeLearn:
When you used the Windows power plan like suggested in the other thread - how far down did you go (just to 50% or less)? I'm not sure what a Desktop CPU uses as 100% for reference, but my feeling is you might need to set really low percentage values before they really affect the CPU running on a single core.

[MakeeLearn]

@MakeeLearn:
When you used the Windows power plan like suggested in the other thread - how far down did you go (just to 50% or less)? I'm not sure what a Desktop CPU uses as 100% for reference, but my feeling is you might need to set really low percentage values before they really affect the CPU running on a single core.

It was at 50% with passive cooling, and there was minimal difference than when at 100% and active cooling. On average my computer was running a modded Skyrim with less strain than running WitPAE.

Turning off the turbo has made a great difference. Both during the orders and action phases. Even though WitPAE crunches a lot of numbers, the turbo seemed to hinder rather than help. Like it was spinning tires instead of going in motion. No loss of performance, actually a gain along with running smoother.

[Rafid]

ORIGINAL: MakeeLearn

It was at 50% with passive cooling, and there was minimal difference than when at 100% and active cooling.

If you want to give the power plan solution another try - set a lower value like 10-20 %. The obvious advantage is that you can change the power plan without a reboot to visit the BIOS (or UEFI). No need if you don't mind the deactivated turbo for other applications of course.

On average my computer was running a modded Skyrim with less strain than running WitPAE.

As I said WITPAE will simply take all available power of one core. Get a new computer and see it taking even more. Skyrim runs sensibly and only takes what it needs.

Turning off the turbo has made a great difference. Both during the orders and action phases. Even though WitPAE crunches a lot of numbers, the turbo seemed to hinder rather than help. Like it was spinning tires instead of going in motion. No loss of performance, actually a gain along with running smoother.

This seems to implicate that excess power is used for something unnecessary with the potential for self blocking. I still believe the engine (or some part of it) has an infinite refresh rate.