Bought a second gtx 460 for SLI and its choppy.

[brehon1104]

Hello,

I just added second gtx 460 for sli and decided to run Metro 2033 in max settings because I believe its the best looking game out right now. It sometimes runs smooth, but other times its real choppy like its having trouble loading something thats happening. I enabled SLI in control panel and did not dedicate anything to physx (set it to automatic).

Is 2 gtx 460's not able to run metro on max settings?


thanks,

Skyler

 

[ghnader hsmithot]

http://www.anandtech.com/bench/Product/314
The last benchmark says it runs at 40fps.

 

[iam2thecrowe]

what are the rest of your system specs. maybe you are cpu limited, or dont have enough ram, or your psu isnt giving enough power to the 460's.

 

[brehon1104]

i5 @ 3.8 ghz
800w corsair
4g ddr3

 

[brehon1104]

I turned Anti Aliasing down to 4x from 16x. apparently my system cant run 16x AA smoothly. I figured it would be able to run anything x.x

Although, on the benchmarks Ghnader posted, it says it ran at 40 fps at 16x. So something has to be wrong. My first guess is some sort of setting:

In nvidia control panel i have it set to automatically pick what processes Physx. Should I dedicate a GPU, select one of my gpus myself, or let nvidia decide?

 

[lowriderflow]

Do you have the newest drivers?! or did you just use the ones that came on the CD with the cards (which are probly a year old)

 

[brehon1104]

Yes sir, always the newest drivers.

 

[Mousemonkey]

So what sort of framerates are you getting and what do you have running in the background?

 

[brehon1104]

I had MSAA 4x on instead of AAA. Apparently this takes a crazy amount of processing power. Once I turned AAA on, I had the predicted 40ish FPS that the benchmarks posted had. (he was also running in AAA). Would anyone care to tell the difference between msaa and AAA?

 

[iam2thecrowe]

msaa reduces aliasing in transperant textures, like between mesh fence wire and tree leaves.

 

[bystander]

msaa reduces aliasing in transperant textures, like between mesh fence wire and tree leaves.

I believe you are referring to adaptive MSAA (an AMD feature that only seems to work at DX9. Nvidia has transparencies for similar results). MSAA typically only works on the outer edges of objects and doesn't help transparencies at all.

Multisampling

Multisampling (MSAA) was created as a faster alternative to supersampling. The basic premise is to find a tradeoff between quality and workload in order to do the minimum amount of extra processing, while reducing aliased edges as much as possible. MSAA does this with two main techniques.

The first technique is edge anti-aliasing, which means that only the edges of objects are affected. The computer renders as much of the scene as possible without any anti-aliasing, but processes extra samples of the pixels on the edge of the object that would benefit the most. Before any anti-aliasing is executed, a Z-test is performed—a difference in depth within a single pixel indicates that it contains the edge of an object and therefore requires MSAA.

The second technique MSAA uses is a reduced-sampling workload. Some calculations are only performed once per pixel, such as for pixel shaders, texture lookups, and color sampling. Only the depth and stencil values are fully sampled. The PC uses this information to determine an optimal blend of color between the object and the background.

http://www.tomshardware.com/reviews/anti-aliasing-nvidia-geforce-amd-radeon,2868-2.html

 

[brehon1104]

Best answer selected by brehon1104.

 

[Mousemonkey]

This topic has been closed by Mousemonkey