Interesting CPU affinity results from WoW
- Thread starter Denithor
- Start date
VirtualLarry
No Lifer
- Aug 25, 2001
- 56,587
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Interesting that the OP in that thread seems to have a physical dual-core CPU with Hyperthreading (4 threads total). What CPU might that be? Since C2Ds don't have HT, and there are no dual-core/four-thread Nehalems yet on the market AFAIK.
Is it some sort of Pentium D EE chip? Did they make any of those with HT? Or is it an Intel Atom dual-core, since those chips DO have HT?
Is it some sort of Pentium D EE chip? Did they make any of those with HT? Or is it an Intel Atom dual-core, since those chips DO have HT?
kami
Lifer
- Oct 9, 1999
- 17,627
- 5
- 81
Yeah i can confirm this. By changing the affinity value in the config file from the default of 3 to 255 my fps in certain situations doubled or tripled. I run the game at 1920x1200 ultra settings and in crowded areas of dalaran this increased fps by about 2x and also a very large increase in raids (up to 3x when effects are heavy). Outside of demanding areas I get upwards of 250+ fps too.
Wow, wonder if this is why my FPS sucked so bad. My card should be fine for everything wow, but it wasn't, and my CPU was only running at 30% load.
- Apr 11, 2004
- 6,298
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I would guess you're right on with a PD-EE. Same setup as i7 - first two cores are 1 physical and 1 virtual - so setting affinity to 3 locks the game onto one physical core and really restricts performance. I find it funny that the blues don't seem to understand that the default setting could really monkey things up when you have an HT-enabled CPU.
kami
Lifer
- Oct 9, 1999
- 17,627
- 5
- 81
Yeah just read the thread for numbers to try. Something as high as 255 will only work on the i7 with hyperthreading enabled (or something else with 8 cores).
I think the benefit is largely for CPU's with more than 2 cores though but it's easy to try different numbers.
Wow, this is really interesting stuff! Although it doesn't effect me currently since I'm running on a single core Athlon64, I'll have to keep this info in mind for the WoW upgrades I'm looking into.
You didn't have this info, in light of that fact had you told them to upgrade to an i7 then your reasoning for doing so would have been lacking. Nothing lame in giving justified advice, but now you have more info to change your advices. No friend should hold that against you
If you set it to 3 and run WoW with task manager in the background and then pop out of WoW over to the task manager how many threads does task manager show WoW was running and at what CPU utilization rate?
Same thing when you are now using 255...does it change the number of threads spawned and/or the effective utilization rate for the cores in any way?
kami
Lifer
- Oct 9, 1999
- 17,627
- 5
- 81
See here: http://i43.tinypic.com/2d0b9eu.jpg
It looks like at 255 its using at least a small amount from each thread.
I knew there was no way it could be. I had a 3.4Ghz e2180 and I was hitting 18fps in Dalaran back when I played; wish I had known about this cause I would have forced it to do more threads; my CPU was only running at 30-40% MAX in that game. I bet it would help even dual core folks like myself.
Anyways I had a huge hunch that something was wrong game-engine side; basically they were using such an old engine and it was simply showing its age when you turned everything up. People with 1GB cards were getting stuttering when they swung the camera around while flying somewhere in Northrend. I thought it might have been my 512MB but I posted about it and other people with way more Vram than I expressed similar frustrations.
This is almost enough to make me want to re-install it and reactivate just to see if I could have been getting 60FPS when I was getting 30 with nasty stutters...
No no no...
This doesn't change the number of threads WoW runs on. The only thing this does is change which cores are available for WoW to run on. Setting it to 255, for example, allows WoW access to all 8 of an i7's physical and logical cores. 85 should allow for only the physical cores, and I believe 15 is the number to set for a non-HT quad-core.
You have a Core2Duo, right? You can't really set yours above 3 (the default setting) anyway, because 3 allows WoW to run on phyical cores 1 and 2... which is all your chip has.
NO! The pain, the agony!!! :brokenheart:
I still don't see why my processor would have only been running at 30-40% and the GPU barely warm...was with vsync off, shadows turned down.
Just curious, but why does this matter? I always ran the game windowed and it would basically max out 1 core and do nothing on the other. That was about half a year ago though.
i can vouch for this. a guildy of mine had an e8600 OCed to 5GHz on chilled liquid cooling, with a 9800GTX, and even with its dual threaded mode enabled the second core wont fully load. i did some testing with my e5200 from 800mhz up to 3.2ghz and the game simply wont fully load the second core when multithreading (dual threading only since i last played) was enabled. consequentially, my FPS in raids with even that configuration still sucks, even though the game was designed to run on 2002 hardware. they are working on moving more and more of the graphics loads to the GPU though, and they hired a graphical engine engineer to do the work, but i havent played since march so i honestly dont know how far they have come, nor have i had a chance to really test my Q9650 @ 4ghz vs my e5200 at 3.2, though i figure i will only really notice a huge difference when dual boxing, something i did rather often lol
ed: if it hasnt been mentioned yet, as far as i can tell, the reason MMORPGs as a whole take so much CPU power is usually similar to the reasons that RTS games with advanced AI take more CPU power. either the game is computing a massive amount of non player character AI and mathematical physics calculations such as damage output + modifiers ect, as apposed to graphical physics, which may benefit more from the crunching power of a large ALU depending on how the code is optimized. simply having a ton of players around eating up physics processing seemed to be the root cause of game slowdowns in EQ2, once i eliminated all graphical aspects of the game still rendered on the CPU, and as an ex 5 days a week 4 hours a day raider, i can tell you the physics in games like these can be quite mind boggling for an outsider. to just jump in and learn all of it is as hard for some as it is to learn 5th grade math and then jump into high school pre-calc, they simply havent built a base in the understanding of game physics like these yet (though most of them are based on simple algebra at most). i would imagine calculating all this math hundreds of times a second would slow things down considerably, especially when you have more people around tossing in multipliers to effects on this math right and left, on top of damage/wards/heals out. it's quite a lot for a CPU to handle on top of running the rest of the game, even today, as proven by how much WoW benefit from this fix, despite being known for running generally quite well on just about any crappy hardware and integrated graphics dating to the 6150LE lol
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