processAffinityMask Testing

[Cilraaz]

So, I saw a few times today where people were mentioning the possibility of gaining a good bit of framerate by setting your processAffinityMask to not use core 1. I thought it sounded insane, but decided to test it out anyway. Here are my results:

Hardware Being Tested
Intel Core i5 750 @ 3.8GHz (200MHz BCLK, 19x multiplier)
4GB G.Skill DDR3 @ 1600MHz; 9-9-9-24-2T timings
XFX Radeon HD 5770 @ stock

Background Processes
Chrome with 21 open tabs (my normal browser load)
Notepad++ for note taking and config.wtf modifications
MSPaint for screenshot management
Task Manager for monitoring core utilization

Test Process
I decided not to go with anything overly scientific. If the framerate gain was going to be anything palpable, it would be noticeable simply by standing in front of the AH in Orgrimmar at peak time. The test was done on the US-Rexxar realm. Framerate averages were done over a 60 second period. My character was not moved during or between any test (nor was the camera angle changed). Obviously other characters moved, but again, if the framerate gain was enough to worry about, it should still be noticeable.

Cores are noted as 1, 2, 3, and 4. Scientifically, they should be 0, 1, 2, and 3, but it's just easier to read this way. All "spikes" mentioned in the below notes were spikes in utilization percentage. The screenshot of CPU utilization was done while idling in game, rather than during any stressful part of the load.

processAffinityMask "15" (Control, as it was already in my config.wtf, all cores enabled)
Average Framerate - 55
Notes: I noted a spike on core 1 after entering my username and password. While the character was loading into game, I noted a small spike on cores 1 and 4. As the character entered the game and became playable, I noted a large spike on core 1.
CPU Utilization:


No processAffinityMask Entry
Average Framerate - 58 (+5.4%)
Notes: I noted no real spike after entering my username and password. While loading into game, I noted a spike in cores 1 and 4. As the character entered the game and became playable, I noted a large spike on core 1. Overall, fairly similar to processAffinityMask "15".
CPU Utilization:


processAffinityMask "14" (cores 2, 3, and 4 enabled)
Average Framerate - 57 (+3.6%)
Notes: I noted a small spike on core 4 after entering my username and password. While loading into game, I noted a spike in cores 2, 3, and 4. As character entered game and became playable, I noted a large spike in core 4. I also noticed (subjectively) that the game loaded noticeably faster (more on this later).
CPU Utilization:


processAffinityMask "12" (cores 3 and 4 enabled)
Average Framerate - 55 (+0%)
Notes: I noted a small spike on cores 3 and 4 after entering my username and password. While loading into game, I noted a spike in cores 3 and 4. As character entered game and became playable, I noted a large spike in cores 3 and 4. I also noticed (subjectively) that the game loaded noticeably faster (more on this later). Once in game, core utilization was noticeably higher than when a total of 3 or 4 cores were available to the game.
CPU Utilization:


processAffinityMask "7" (cores 1, 2, and 3 enabled)
Average Framerate - 58 (+5.4%)
Notes: I noted a small spike on cores 1, 2, and 3 after entering my username and password. While loading into game, I noted a large spike in cores 1 and 3. As character entered game and became playable, I noted a large spike in cores 1, 2, and 3. I also noticed (subjectively) that the game loaded noticeably slower again, similar to processAffinityMask "15" or no entry (more on this later).
CPU Utilization:


processAffinityMask "6" (cores 2 and 3 enabled)
Average Framerate - 56 (+1.8%)
Notes: I noted a small spike on cores 2 and 3 after entering my username and password. While loading into game, I noted a large spike in cores 2 and 3. As character entered game and became playable, I noted a large spike in cores 2 and 3. I also noticed (subjectively) that the game loaded noticeably faster again, similar to processAffinityMask "14" and "12" (more on this later). Once in game, core utilization was noticeably higher than when a total of 3 or 4 cores were available to the game.
CPU Utilization:


Load Times
After noting subjectively that the load times seemed faster when core 1 was not in use, I decided to time how long it took my character to load into game. I loaded with no processAffinityMask entry, a setting of 15 (all cores), and a setting of 14 (cores 2, 3, and 4). The timer was stopped when the game world was viewable, not when characters were fully loaded or high-res textures were fully loaded, as that would be testing I/O and not CPU. Each was done three times and the average value is shown below:

• processAffinityMask "15": 15 seconds
• No processAffinityMask Entry: 15 seconds (+/- 0%)
• processAffinityMask "14": 11 seconds (-26.7%)

Conclusions/Results
Well, it seems like there is no real framerate gain to be had by doing this on a non-Hyperthreaded CPU. Removing the virtual cores from being used on a Hyperthreaded CPU may show some gain, but I have no way of testing that. The maximum framerate change was 3fps, or 5.4%, which is easily within margin of error, considering the lack of control I had over other characters in the game. The odd thing seems to be the load times. Logically, there's no reason that eliminating core 1 from being used should lower the game's load time, since that's mainly I/O based while addons are loaded. I'm also not certain if there's some odd caching going on in the OS that's letting it load faster at some times. The results seem pretty conclusive, though.

Again, I have no way of knowing if framerate gains are to be had by changing processAffinityMask on a Hyperthreaded CPU. I simply don't have the hardware to test. If you'd like to test it, please feel free. Try to keep the test similar to mine, however, as that would give the most uniform results. Any feedback, thoughts, observations, or critiques are also welcome, if they're constructive.

[BicycleMafioso]

Interesting. I will probably try to conduct testing of this myself. I want to say tonight, but it's 3.30am, and I need my sleep, and my schedule is full tomorrow (arena, orgrimmar-raids, RL-stuff), and going away a week starting Monday.
If my memory reminds me, I should want to start to try this as soon as possible.

Your results intrigued me. I shall try to get a sample-size of ~4-8 per setting. I will also try it with VSync disabled, in a pre-designated area. Is there any way to monitor average framerates?

[Cilraaz]

Is there any way to monitor average framerates?

I used fraps to capture a 60 second timeslice and calculate the average for me.

[Deleted]

I'm also not certain if there's some odd caching going on in the OS that's letting it load faster at some times.

You did account for Superfetch I hope?

[BicycleMafioso]

I used fraps to capture a 60 second timeslice and calculate the average for me.

I figured as much. Regrettably, I don't have the money for that.
I assume the 30second-trial is too short to be conclusive.
I also have WoW on an SSD, so the differences in loadtimes when it's at 5-6 seconds already i quite indiscernable, I imagine. D:
I'll poke around some tomorrow.

[Cilraaz]

You did account for Superfetch I hope?

Superfetch caching addon data? Doubtful. Superfetch caches the most commonly used executables, not data those executables access. Also, it wouldn't account for the increase in load time from processAffinityMask "12" to processAffinityMask "7". Tests were done in the order listed.

[llDemonll]

since i've never delved into it, how do i set process affinity masks? i have an i7 920 at stock clocks and would be happy to post results

[Dethh]

since i've never delved into it, how do i set process affinity masks? i have an i7 920 at stock clocks and would be happy to post results

There is a guide here http://www.mmo-champion.com/threads/...tweaks...Guide

[nwo]

What setting would you recommend for an i7 sandy bridge laptop?

[H3ll]

What setting would you recommend for an i7 sandy bridge laptop?

Return it, sandy bridge cpu's have a huge problem, read: http://www.engadget.com/2011/01/31/i...ments-stopped/

[EverFX]

Hmm, this is quite interesting.

I imagined that altering this setting would just give you a decrease in performance since you are essentially limiting Microsoft's scheduling algorithm to a specified number of cores. Seeing as how it has minimal effect, I imagine any performance gains solely relies on the OS's ability to multiplex the process to a proper core.

I doubt Blizzard would be silly enough to purposely limit themselves to Core 0.

[Wries]

Return it, sandy bridge cpu's have a huge problem, read: http://www.engadget.com/2011/01/31/i...ments-stopped/

The CPU's don't have any problem. The chipset controller for SATA 3Gbps is. Many laptops may not use this controller and are thus unaffected. Best thing to do is to wait for the manufacturer of the laptop to give a statement about what type of SATA ports were used when building it.

Furthermore I can witness to that in W7, WoW does get way faster loading screens after you've recently closed the game and reopened. It probably doesn't get erased from the system ram.

Think I will try this with my i7 tonight. I'm already fairly certain that either W7 or WoW itself places at least most of the computing on the physical cores without any manual processAffinity being set, but statistics are always juicy.

[Deleted]

Chrome with 21 open tabs (my normal browser load)

?

Post requires 10 characters but i have nothing more to say.

[nwo]

?

Post requires 10 characters but i have nothing more to say.

What's wrong with that? I typically have at least 10 open myself. A few youtube songs/videos, a few forum tabs, e-mail, etc, it all adds up

[Asera]

With tab stacking in Opera 11 I end up having 30 or 40 tabs open sometimes without realizing.. @_@

[DarkBlade6]

Hey what would be the ProcessAffinityMask to make sure WoW do not use any ''HT Core'' on a i7 ??

[Deleted]

What's wrong with that? I typically have at least 10 open myself. A few youtube songs/videos, a few forum tabs, e-mail, etc, it all adds up

How can you listen to many songs at once? I dont use Youtube for music anyway.
Winamp.

Anyway i cant even think of 22 websites that i visit..

[Asera]

*deep breath*

mmo champion (2-3 tabs)
Youtube (anywhere from 1-5 tabs, if people are linking me music to try, I leave them open instead of copying the band down cause I am bad!)
Gmail (Temporarily due to my exchange server being down)
wikipedia (usually 2 tabs, browse at work when bored to gets the infos)
nhl.com
battle.net (2 tabs, usually armoury and the forums)
XKCD, C&H, VGCats... (usually not all at the same time)
My friends file hosting page
various things I've googled/binged and forgot about.
Fedex.com tracking (work)
Federal Standard Colour System page
Pantone PMS Colour System page
XDA Developers

yeah...

[Deleted]

With tab stacking in Opera 11 I end up having 30 or 40 tabs open sometimes without realizing.. @_@

Now where the fuck did I put...

Oh.

Kinda had to start using Session Saves after that. (And use the Speed dial with autorefresh active)

[Soisoisoi]

I'm not very technical, but my brother put SET AffinityMask "80" into my Config after reading the guide what came up a week or so ago and my FPS went up slightly, something to do with running WoW from Core 2&3 but not 1(or something like that). If this makes any sense to you, hope it 'helped' in some way.

*This was just stood in Hyjal my FPS went from about 39-46 to 42-50ish(just stood still out of combat - not got a great PC) with nothing changing but that line into config.