How do I stop SLI from doing THIS? (I hate SLI...)

[skypine27]

To start off, I know Vista 32 will never be able to show all 4 gigs of ram. I hope sooner or later Vista 64 is reliable enough with games to make it worth while. I'd switch to that and slap in 8 GB if it was.

However, I have 4GB installed in my Vista Ultimate 32 system. With one PNY 8800 Ultra installed, all Vista screens show 3.25GB available (in control panel / system info screen and in the boot up "welcome to" screen)

See screen shots:



screen 2



However, when I install a 2nd PNY 8800 Ultra in SLI, the available ram drops to a whopping 2.5 GB (and Vista RAM score drops from 5.9 with one card, down to 5.6 with two)



screen 2



It appears to me, that somehow these cards are "using" my system memory, as well as their own 768 MB on each card. (Kind of like a laptop). Is there anyway to stop this??? I would like all 3.25GB available to Windows!

I swore when SLI first came out, that it would be a short lived fad and would quickly fade away (just like multiple CPUs on the same motherboard. Remember back when you could get two 486 DX2s @ 50 mhz on the same mobo! Man that was cool...) In any case, it looks like SLI is here to stay a while, and I'd like to be able to actually use it (In Vista)

Thanks guys

[Un4given]

As I understand it, it's a bug in Vista in reporting of memory. You may want to use something like CPU-Z to see what it reports for available memory.

[skypine27]

CPU-Z always shows 4 gigs of ram (when I have all 4 dimms installed)

but I believe this is different from the issue Im talking about above, where adding a 2nd video card lowers the amount of memory that Vista can "see"

[OpStar]

Its because the BIOS/Windows use some of the physical address capabilities (which is capped at 4GB) for the video ram. That is why approximately 768mb more is lost in SLi.

There are lots of articles about it if you Google.

[skypine27]

Crap. You were right about the articles on google...

http://www.custompc.co.uk/blogs/gare...o-memory-loss/

[blitzekriec]

Nemesys posted this link in another thread a little while back, and the article will clear up why it's happening.

According to this article, you will actually see a much better result if you only install 3GB of memory, since the amount of RAM lost from peripherals is minimal.
So running SLI on a 32bit system is feasible, as long as you have a max of 3GB of RAM installed.