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M9700 Single GPU bandwidth wrong?

post #1 of 3
7/12/08 at 11:25pm
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I have an SLI setup for my desktop, it has either a x16 PCie slot or if you put in both cards its two cards running at x8 PCie bandwidth.

Now my M9700 currently only has one card (i'm still looking for another and SLI cable) butit shows as x8 as the bandwidth. Is this correct even for a single card?

Seems it should be at x16, or is there some trickery they did with the mobile platform of SLI.

Randy
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post #2 of 3
7/12/08 at 11:36pm
The m9700 was designed and built at the time before SLI was built into the mobos. It uses a desktop nForce4chipset to run it, combined with mobile cards, so it's a bit of a frankenstein.

I'm no expert on SLI, but as I understand it, the gpu slots each have 8x pcie, and the bridge cable handles the communication between the cards, some of which now runs through newer mobos with dual 16x pcie slots.

Not really sure why SLI continues to need the bridge, as crossfire works entirely through the mobo at this point.

Really doesn't answer your question I guess... How are you finding the reported bandwiedth?
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post #3 of 3
7/12/08 at 11:44pm
Thread Starter 
Quote:
Originally Posted by Hammerhead View Post
The m9700 was designed and built at the time before SLI was built into the mobos. It uses a desktop nForce4chipset to run it, combined with mobile cards, so it's a bit of a frankenstein.

I'm no expert on SLI, but as I understand it, the gpu slots each have 8x pcie, and the bridge cable handles the communication between the cards, some of which now runs through newer mobos with dual 16x pcie slots.

Really doesn't answer your question I guess... How are you finding the reported bandwiedth?
A desktop MB such as the a8n-sli has two PCie slots with a total of x16 bandwidth avialable, so one card gest it all or two share it at x8 each.

As for finding it, its in the Nvidia control panel.

In fact I finally bought a new MB, a A8n32-sli, which has two full x16 PCie slots, so that there is no wasted bandwidth when you have two x16 cards. And boy does it fly.

I wonder is just installing the SLI able is enough to "trick" the MB into running in X16 mode? I doubt it though, my guess is that its two x8 slots that finally get you x16 when in SLI.

So in SLI its the same as early desktop SLI modes, but in single GPU, there is a penalty.

Randy
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