Arma Core Affinity

[Yoma 0]

Some users of my Addonsync tool asked me if it would be possible to launch arma with affinity to for example core1 instead of core0 & 1.

This is probably technically possible. However before implementing it, i did some basic testing (on VistaX64) and come to the conclusion that on my system setting affinity to for example core1 actually slows down the game instead of speeding it up. This could be due to multicore optimisations in the Nvidia drivers, i don't know but all i can say is this:

GPU 8800GTX

CPU E6750@2.66

Armamark with core affinity set to core1

-first run: 3214

-second run:3653

With core affinity set to both cores

-first run:4073

-second run:4642

Back to core affinity set to core1

-only run:3240

Of course this could only be on my system but i think maybe the whole "set the game to use 1 core" may not be helpfull for performance at all.

Could you guys do some testing on your systems to see if you get the same behaviour? I don't want to implement it in my tool if using it would only slow down the game.

[gL33k 0]

if you want proof,try to disable multithreads optimization from nvidia panel. and do it again.

[Yoma 0]

Well if i do that scores are marginally lower (like a deviation of 50).

My actual question is: on my system arma runs slower when i put it on 1 core. How does it run on your systems?

It looks like running it on one core is NOT a good idea. Also maybe stuff starts to change with quadcores where you can put it on 2 "free" cores.

[andersson 285]

I did some affinity tests for arma on my C2D6600E.

I got the best results from default settings.

I tried to have arma.exe at 0 and 1. I also tried to have everything at 0 and only arma.exe at 1. I did not see any benefit, the opposite actually.

I was playable for sure and no much drop in FPS (fraps), but it was choppier. The core that arma.exe was on had 95+% cpu usage, no matter what combination I had. When I have it default the average drops to ~60% on both cores (unless cpu intensive situations in the game ofcourse).

So default settings gives more cpu usage in total, and less strain on one the cores. Changing the affinity settings for arma.exe was noticable ingame as it gets more choppy, not much but noticable. It also put alot of strain on that core.

I am not interested changing affinity on my system regarding arma. I have the best performance default.

edit. To add, I have windows XP pro, SP3 and updated. Also good and stable drivers for arma overall.

[Yoma 0]

Ok so you come to exactly the same conclusion as me.

I bet there are some hidden multicore optimisations, maybe the caching of textures/data gets somewhat optimised by windows itself on multicore. Now for someone with a fancy quadcore :-) Come on guys don't be lazy!

[SWAT_BigBear 0]

Mine isn't "fancy" anymore....but I see the same as you guys.

Running our private server on the same box does though. We get better games pinning the server to any 1 of the 4 cores.

[paragraphic l 2]

I never checked it, but setting affinity to 1 and then having that core's priority run at Real-time always made my game FEEL smoother.

When I have the time I will properly test this offcourse.

[bhaz 0]

I've got a Quad Q9400, not too good but not too bad either. Affinity didn't really make a difference for me, the only use I found of it was running a dedicated and client off the same machine and that made a massive difference.