I have a quick question, I am curious as to whether the north bridge could impact performance or be a bottleneck if I were to buy two 9800 GX2's for my current rig. My motherboard uses the n750i north bridge, and it's a pci express x16 2.0 board, so as far as pci express bandwidth I should be covered, but I was curious if the nb impacted this at all, or if 9800GX2s in sli would work out with it at all? Also, sort of related, does anyone know the length measurement of a 9800GX2? I believe one would fit in my case, but it'd be good to find out ahead of time. How about connectors? two 6 pin? or are they differ from the norm? Thanks!!! -Rob
The Northbridge should not impact graphic performance directly, but will/may impact performance due to memory management (compared to other chipsets). However, it should not be noticeable in games or anything really. I do think the 750i is a X16 + X8 PCI-E2.0 solution though, not a 16X16, which is 680/780/790? That might slightly hinder performance if I am correct, since you are running a GX2 on the slot. Though negligible performance hit. It is 1X6 + 1X8 pin PCI-E connectors each = 2X6pin 2X8pin total 10.5 inches in length, which is the same as GTX260/280 8800GTS/GT are 9inches in length. However, Quad SLI does not yet show huge benefits across all games, so keep that in mind.
Alright, nice response! thanks a bunch, I'll keep all that in mind, very informative. Also, I'm curious, see, since my motherboard is pci express x16 2.0, right now I'm sli'ing two 8800GTS's (640mb) and they're running at 8x each, now I know that they only support standard sli anyway (they're just pci express x16 cards, not 2.0 compliant) but my motherboard says it's pci express x16 2.0. SO does that mean if I had two pci express x16 2.0 cards they would still run at x16 standard bandwidth each, even if they showed up as 8x? (since it would really just be half of 2.0 bandwidth, which would still equal out to regular x16 bandwidth?) Sorry if I am vague or bad at explaining what I mean, but I'm really curious on this matter. And I swear, I've googled everywhere and just can't seem to find the exact answer I need, just lengthy answers on the history of pci express x16. and 2.0 bandwidth. Thanks a bunch for your help! PEX16-1: PCI-Express Gen2 x16(x16/SLI x8 Speed) Slot - PCI-Express 2.0 compliant. - Maximum theoretical realized bandwidth of 8GB/s(4GB/s SLI) simultaneously per direction, for an aggregate of 16GB/s(8GB/s SLI) totally. - PEX16-1 slot is reserved for graphics or video cards. The design of this motherboard supports dual PCI-Express graphics cards using NVIDIA’s SLI technology with multiple displays. When using SLI, this slot is master and runs with x8 speed. - To configure for SLI, please refer to the instructions of configuring JPSLI1~JPSLI9. PEX16-2: PCI-Express Gen2 x16(NC/SLI x8 Speed) Slot - PCI-Express 2.0 compliant. - Maximum theoretical realized bandwidth of 4GB/s simultaneously per direction, for an aggregate of 8GB/s totally. - PEX16-2 slot is reserved for graphics or video cards. The design of this motherboard supports dual PCI-Express graphics cards using NVIDIA’s SLI technology with multiple displays. This slot is slave when using SLI. If PEX16-1 is set to x16 speed, then PEX16-2 would not be functional. Also that is an exact quote from my motherboard manual, could you help me decipher if that means I could get the bandwidth I'm talking about?
Both the Asus and the Evga 750i uses two 16x 2.0 PCI_E bus.. donno what other brands like msi have on theirs.
The part from the manual probably just means that... When SINGLE card ... Slot 1 = 16X Slot 2 = not operational Dual Card (SLI) Slot 1 = 8X Slot 2 = 8X Since they are PCI-E 2.0 slots, then it would (should theoretically) equal PCI-E 1's X16 bandwidth when combined with a PCI-E 2.0 card. I think its alright, nothing to worry about. However, noting your profile, I would personally think a 700W power supply might not be enough for 2X9800GX2s, but not really sure on it. Should work, but might stress it a bit. edit: 750i does not support 16X16 as far as I read on the nvidia site o_o the other boards probably use another bridge chip, since the 750 only supports 26 lanes (16X1 8X1 2X1)
Hey, thanks a bunch for your help guys, and I saw that on nvidia's site too, that the 750i has 26 lanes, yet the board specifically states both slots are pci express x16 gen 2 compliant (aka 2.0) So I'm still curious as to whether I'd get regular x16 bandwidth on both (when sli'ing, 8x of 2.0 on each) I really hope I can! I think it'd be pretty sweet to sli two 2.0 cards. And as far as power supply usage goes, I calculated using a wattage calculator (and mentally, noting wattage requirements for my parts) and you're right, it'd probably be a good idea to get a slightly better psu, however it did come to just below 700W. (About 650-680) and yes that would be under FULL load. So I'd just have to see. Thanks so much for your help guys, and I sure hope I can find an answer to whether having both slots being 2.0 compliant, could mean regular x16 bandwidth in sli. Also, take a look at this link, what do you make of the thread? http://www.overclock.net/intel-motherboards/389328-does-750i-ftw-support-x16-sli.html
