Specs:
- intel Core2Quad Q6600 G0 @ 2.4GHz
- Asus Rampage Extreme X48
- G.Skill Ripjaws-X Series 4GB (2x2GB) DDR3 1600MHz CL6 RAM @ 1066MHz CL6
- Nvidia Geforce 285 GTX 1GB-DDR3 x2 SLI @ 16x/16x "using SLIPatch 1.5b"
- Gigabyte Odin Pro 800w PSU

* OS: Windows 7 Ultimate 32Bit
* Nvidia Driver = 280.26 WHQL
** Using 285.xx driver doesn't work ! can't enable SLI in Nvidia's CP and can't run rage on single card !

RAGE Patched and updated + rageconfig.cfg settings :

vt_pageimagesizeuniquediffuseonly2 8192
vt_pageimagesizeuniquediffuseonly 8192
vt_pageimagesizeunique 8192
vt_pageimagesizevmtr 8192
vt_restart
vt_maxaniso 4
image_anisotropy 4
vt_useCudaTranscode 1

Ingame Settings:
- Resolution: 1024*768
- 4xAA
- vSync: off
- Texture Cache: Large
- AF: High

This pic shows RAGE stressing both GPU's :
[img]http://img6.imageshack.us/img6/451/ragesligpu.jpg[/img]


Using 8K textures loads more than 800MB on both cards "totaling more than 1.6GB" !

Game runs smooth 60fps, drops to 44fps when using 16xAA but over clocking my Q6600 to 3.2GHz and RAM to 1600MHz rises frames to 60fps and drops to 55fps.. "damn bottleneck"

Noticed that some times the screen flickers like SLI is going out of sync or something and I'm forced to exit and run the game again..

Forcing 16K textures through rageconfig.cfg makes the screen becomes blue and loads about 300MB on both cards "600MB total" ?! so how much VRAM I need to run 16K ?

I want more "eye candy", can I tweak it more ?

BTW, I've just finished "Dead City", damn this is an Awesome Game !

I'm pretty sure SLI or CFX will only use the memory of one card. IE if you have two 1GB cards, your video ram still = 1GB and if you have three 2GB cards your video ram = 2GB etc.

No that's not true, Enabling SLI will split workload on both GPU's and uses both card's VRAM !

For that, putting 2 cards in SLI that uses the same GPU but with different memory size like the 2GB and 1GB version of GTX-285 will made the driver address and use only 1GB of the first card "2GB version" and 1GB from the second card and split the load on them, so that they are totaling 2GB !

Also, the driver will clock both cards at the same speeds (if they are not identical) so that they'll work together in full sync.

BTW.. RAGE requires 1.5GB+ for 8K textures !

I'm not saying I don't believe you but what I've read contradicts what you are stating. For my own edification, can you point me to something that confirms this?

I guess not.

http://www.tomshardware.com/forum/308730-33-6xxx-series-crossfire-combine

It looks like I was right. The cards just mirror the vram data. The memory does not combine. Although both GPU's will be utilized, two 1GB cards will still only give you 1GB of effective video ram. Hope this helps.

The memory in both cards is duplicated, as one can not draw a frame without having the same texture data as the other card.
If card #1 reads 0,9 GB, card #2 needs to have the same 0,9 GB loaded to render the game synchronously with the other card.

So while the total memory usage can look like eg. 1,8 GB, it's just because both cards have loaded the same 0,9 GB of data.

And no, you don't 'need'/game doesnt 'require' 1.5 GB for the large texture cache. I have a 1 GB HD 5850 running 1920x1080 with 8x MSAA and everything to the max, it runs flawlessly and the game vram usage is at 800-950 mb vram.

The game just scales to how much VRAM you have, so possibly less texture popin (though I have none already, more vram will be needed for higher resolutions like 2560x1440 with anti aliasing). The consoles use the same texture resolutions for textures, but have only 256 MB vram which is why they have to swap memory a lot more often from the slow disk, causing significant texture pop.