7800gtx 512mb and 256mb in SLI?

P

PCG_Norman

n00b
Joined
Jul 7, 2006
Messages
18
Nvidia says this is possible, but I can't for the life of me get it to work. I have a 7800gtx 512mb card and a 7800gtx 256mb card, both running on my asus a8n-sli mobo. I've tried enabling coolbits (with values 8, 18, and 1A), installed the newest bios and drivers (rev 90), but the control panel still won't let me enable sli, even though the system detects as sli capable.

After hitting the enable SLI rendering mode button, applying, then restarting, the button just goes back to non-SLI mode. How can I fix this (ie. only utilizing only 256mb of the 512mb card)?

Thanks.
 
Can I mix and match graphics cards with different sizes of memory?
While it is not recommended, NVIDIA does offer this flexibility using Coolbits. When purchasing a second graphics card, you should try to match the memory size so that you are ensured full value and performance from your purchase. For example, if your first card is a GeForce 6600 GT with 128MB of memory, you should purchase a second GeForce 6600 GT with 128MB of memory. However, using Coolbits (value set to 18), customers can force both of the cards to use the lower of the two memory sizes and operate together in SLI Mode. When dissimilar memory sizes are enabled to work together using Coolbits, the effective memory size for each card becomes the smaller of the two memory sizes. Instructions to enable this feature can be found here .
 
I've tried that, but i don't get the "sli rendering mode" option in the advanced setings part of the performance & quality settings.
it jumps from triple buffering to negative LOD bias.
i think the "sli rendering mode" settings are only there if sli is enabled, which my computer won't do.

i've driver cleaned and reinstalled the newest drivers....any other suggestions?
 
It probably won't work. Despite the name, a 7800 GTX 512MB is not even in the same class as the 7800 GTX. I imagine the software treates the 512MB model as an "Ultra" version, much like the 6800 GT versus the 6800 Ultra: the only difference is clock speed, but you can't SLI them.
 
Too bad you coudnt find you another cheap 7800 gtx 512, in sli they are unreal. I still think the 7800 512 is the best card ever made, shame they didnt stick around long enough.
 
yeah, i'm going to sell my stock 7800gtx and try to buy aother 7800gtx 512. hopefully the price difference won't exceed 100 bucks.
thanks everyone for the tips.
 
you would be better off selling both cards and getting a single 7900GTX.
 
D!Z said:
Too bad you coudnt find you another cheap 7800 gtx 512, in sli they are unreal. I still think the 7800 512 is the best card ever made, shame they didnt stick around long enough.
Click to expand...

i thought 7800GTX's were going to be the G70 or G80
 
7900 series cards use the G70 Core.

G80 is new DX10 cards, rumored to be the 8000 series cards (ie: 8900GT, etc)
 
Faction said:
you would be better off selling both cards and getting a single 7900GTX.
Click to expand...

the funny thing is that i traded a co-worker my 7800gtx for the 7800gtx512 and 7800gtx 256.....i thought i would get better speeds with sli.

damn him!
 
PCG_Norman said:
the funny thing is that i traded a co-worker my 7800gtx for the 7800gtx512 and 7800gtx 256.....i thought i would get better speeds with sli.

damn him!
Click to expand...

Wait...

You traded a 7800 GTX for:

A 7800 GTX 256
A 7800 GTX 512

What the hell is going on here :D
 
The 7800GTX 512 is gonna be nigh on the same performance as the 7900GTX anyway. Sell the 256 and get hold of another 512. You won't regret it, it kicks ass :D
 
You must log in or register to reply here.
Back
Top