VRAM question.

[dmxdex2020]

I have a geforce 470 1gb and i know that with a lot of mods oblivion is very hungry for VRAM. Im adding another 470 for sli soon. With a lot of mods will oblivion use my of my cards VRAM? I heard it would only use one of my cards memory.

[HeyYou]

Going SLI does NOT effectively double your Vram. The benefit is from both cards building the scene. They both have to have all the assets loaded. You may see a bit of performance increase, you may not. It's really a crap shoot.

[dmxdex2020]

Going SLI does NOT effectively double your Vram. The benefit is from both cards building the scene. They both have to have all the assets loaded. You may see a bit of performance increase, you may not. It's really a crap shoot.

 

I looking into another 470 for sli because i have a lot of the new shaders running which kill peformance notable HBAO. My second card is not just for oblivion.

 

Ok when you have 2 cards were is the extra performance coming from if not the memory? the core clock?

Edited May 29, 2011 by dmxdex2020

[MotoSxorpio]

Comes from the two cards working to render your scene at the same time, but doesn't "stack" your vram size. They both have to hold the memory to render it.

[HeyYou]

And you don't get 100% performance improvement by adding a second card either. With Oblivion, I have seen reports all over the scale, highest being a 20% improvement, worst being a 10% LOSS of framerate. As opposed to buying a second card, I think your money would be better spent upgrading from the card you have now.

[MotoSxorpio]

true, HeyYou. its a hit or miss on SLI. I got mine to work, but it took some time and I am not sure what exactly I did to do it. Like nothing jumps out except redo the Video Check Tune thing when you insert the disc. But that regenerates the INI, so be sure to backup your original INI and compare afterwards, if you try that.

[dmxdex2020]

Like i said im not getting a second card for just oblivion its for my other games and battlefield 3. I have heard i should see a nice improvement with SLI on oblivion. Time will tell.

[ArmeniusLOD]

I would recommend getting a second card for your other games. Oblivion is CPU-bound, so you won't see much of a performance increase, if any at all. However, for newer shader-intensive games you should see a large increase in performance, sometimes doubling. Battlefield 3 will probably be a game that scales very well. I have a SLI system, and performance in Metro 2033 for me is close to double compared to a single card.

 

A note about VRAM usage. Most implementations of SLI are alternating rendering the frames on screen, so each card is rendering a separate frame. Meaning that the max size of the framebuffer is still the amount of memory on one card, in your case 1GB. The only implementation I know of that renders a single frame using both cards is with SLI AA enabled. 32x and 64x anti-aliasing isn't all that impressive anyway, plus the performance penalty in these modes is extreme.

[MichikoUnknownFox]

I'd imagine that VRAM isn't as important in Oblivion (as with most games) as is the actual speed of the GPU. There are high end cards that have only 256 MB VRAM, but are ridiculously faster than my 8600 GT with 1024 MB.

 

For the most part, 1 GB is more than enough to load even high res textures, but the problem is that the GPU and the swap rate aren't fast enough to actually process all of the 1 GB RAM, so it's not like it's an actual benefit.