what dictates the speed of a PCI-E lane?

I mean, Ive got two for crossfire on my Asus Mobo, but in the manual it states that only one lane is 16x while the other is 8x or 4x....its kinda lame

Usually, with Nvidia's other chipset monikers, it would state it in the packaging and on the box. SLI X16 or true SLI or support for Dual X16 PCIe lanes. Along those lines. Kind of stupid for them to be so finnecky with some main boards, especially if its their own chipset :shadeshu

Wow, could this be the first GPU that isn't made in AGP flavour as well xD Or then it is and nvidia just made a deal with mobo companies, so that it doesn't work on 8x and peeps have to buy the newest motherboards as well :P

ex_revenwhat dictates the speed of a PCI-E lane?

I mean, Ive got two for crossfire on my Asus Mobo, but in the manual it states that only one lane is 16x while the other is 8x or 4x....its kinda lame

I'm not an expert on the subject, but here goes a try. Northbridge has only a limited amout of PCI-E lines, like my nForce4 has 20. so 16x goes to GFX and it leaves 4x free and this mobo has 3 times PCI-E 1x (one does nothing).

Now the first SLI was simply made made cutting the one 16x in half (with that littlemotherboard sli brindgethingy. If one card was used, you could get the whole 16x. Now to get full 16x to 2 graphic cards, you need two northbridges, one providing the usual stuff and the other the extra 16x lines for second graphics cards.

some copypaste to explain it more

"Nvidia's top of the notch AM2 chipset uses two north bridges. First one called Nforce 590 SLI SPP provides PCIe 16X. The second Northbridge acts as a south bridge and is branded as Nforce 590 SLI MCP - Media Communication Processor. The south bridge chip provides an additional PCIe 16X slot, two times Gigabit LAN, HDA Azalia audio, 10 USB 2.0, five PCI slots, 4x1PCIe, two IDE hard drive controllers and finally six SATA II ports. It is a nice chipset and we already tested a few boards using it."

Don't know how much a northbride costs, but can't be free and older cards worked just fine with PCI-E 8x.

OnBoardDon't know how much a northbride costs, but can't be free and older cards worked just fine with PCI-E 8x.

If you can afford 2 8800's you can also afford to spent a bit more on your board.

Hehe, true :) But more of a principal issue. Like if AM2 had the same pins in same spots as 939, but it just wouldn't start on sockect 939 motherboard, because AMD wanted to prevent it, surely you'd like to have a modified bios before a new motherboard.

I don't see this as a big problem. I have had no trouble with my GTX on multiple boards, and I understood I would need a 16x2 board to use SLi when I bought the thing - People who use the card on boards without a 16x slot will likely be pairing it badly with the CPU (and rest of system) anyway...

So does this mean that it wont work with a PCIe x 16 slot that has been electrically diled down to x8 (like with SLi/Corssfire), or a only a physical PCIe x8?

TrackSo does this mean that it wont work with a PCIe x 16 slot that has been electrically diled down to x8 (like with SLi/Corssfire), or a only a physical PCIe x8?

Both.

zekrahminatorBoth.

That dosen't make a lot of sense.

We would have already heard from hundreds of 8800 GTX owners that their motherboard dosent support it. We would have known a long time ago abt the x8 problem because they would have told us.. seems like a big issue to me. I mean, there must be thousands of ppl out there with motherboards that only support x8 with SLi.

It is a big issue and one Nvidia should be punched in the face for. I havent seen where it says it needs a full 16X PCIe lane dedicated to it or anything of that nature. They should have put something out saying what works with it (For the record, if they did, Im sorry, I didnt see it :( )

it wont work b/c Nvidia prolly told the card not to just like intel did with their C2D chips :shadedshu its marketing nvidia makes more money if you purchase new chipsets liscensed by Nvidia

Um, nVidia said very clearly it was 16x SLi only, if people choose not to read enough that's not their fault...

Clearly? Hardly.

There is no reason for the 8800s not be compatible with PCIe x8.

I read something about this yonks ago, if I remember correctly supposedly the 8800s would work in 8x configs, but just be bandwidth limited. I suppose a possible solution to the no boot problem would be to increase the PCI-E frequency and see if the card would then work - having additional bandwidth available.

It wont be a bandwidth problem, it's bound to be a pin-out problem or similar, wherein the routing for 16x is different from 8x, and the 8800 doesn't do the 8x properly...

Either way I think people are making a mountain out of a molehill. There isn't an 8x SLi board I would use 8800's on anyway, an AMD or PD chip would kill two 8800's...

either suggestion seems unlikely. id put more weight in nvidia just dropped 8x support completely and didnt bother telling anyone.

Hence my point... Must have been hard to create a PCB that works well with 8x, so they didn't...

no hard, more the lack of bandwidth crippled it, so they dropped support entirely for 8x and figured theyd try milking the cash cow some more to get ppl buying new NF4\5 boards as well.

Ketxxxno hard, more the lack of bandwidth crippled it, so they dropped support entirely for 8x and figured theyd try milking the cash cow some more to get ppl buying new NF4\5 boards as well.

see thats what i said