PCI-Express 2.0: Will GT200/R770 need the bandwidth?

[Zinthar]

I'm deciding between purchasing a P35 motherboard (the DFI LT P35 T2R) or buying a similarly-priced used X38 board on ebay (probably either a Gigabyte X38 DQ6, the DFI LT X38, or the Asus Maximus Formula). I'm fully versed in the differences between the two chipsets and have no plans to run a CrossFire setup. The only benefit I'd get from running X38 would be the addition of PCI-Express 2.0 for future video cards, and it would come at the cost of 20-30% extra power consumption of a similar P35 configuration.

I know this question forces speculation about the future (esp considering knowledge of GT200/R770 is limited), but what do you guys think about the necessity of PCI-Express 2.0 support over the next 2 years or so? I currently have an 8800GT, and will almost certainly replace it with a high-end single card solution (a non-GX2 or X2 card) next year for Alan Wake. I have a Q6600 running @ 3.2 Ghz, so I feel like I'll probably be good on the CPU side for that timespan and I'd hate to have to upgrade my chipset just for graphics card support.

I've only been building PC's for 2 years now, so I don't have a frame of reference for how quickly PCI-E bandwidth was needed over AGP, and so on. So, will the PCI-E x16 support of a P35 chipset be enough to not adversely affect my minimum framerates w/ next-gen single cards?

 

[error8]

From what I know the G80 8800 GTX use to fill PCI-Express 1,1 8X bandwidth, but it was a long way to fill the 16X, so I guess that if the GT200/R770 will have double the speed, could get close to fill all the bandwidth, but it won't really use it all. It's pure speculation, but it seems logical that this year the "old" pci-express will still do it's job. Even if the new cards will cross the limit of the bandwidth , it won't cross it by much so the loss in performance will not be important.

 

[betasub]

There's an article at Tom's Hardware that attempts to address some of these questions.

In brief, it concludes that it's as much about the application/game as the card itself: if the textures used require more memory than available onboard (vRAM) e.g. FlightSim X, then PCIe bandwidth can become a limiting factor for a high-end GPU.

 

[Zinthar]

Originally posted by: betasub
There's an article at Tom's Hardware that attempts to address some of these questions.

In brief, it concludes that it's as much about the application/game as the card itself: if the textures used require more memory than available onboard (vRAM) e.g. FlightSim X, then PCIe bandwidth can become a limiting factor for a high-end GPU.

I just read that article as well. In those situations though it would seem that you're not going to be in a good position, performance-wise, if you have to start accessing the system RAM -- and theoretically cards with more vRAM won't be as susceptible to those issues -- lowering the resolution would probably have made the limiting factor something else (I don't consider mid-20's performance to be acceptable anyway). I'm thinking I would be better off just keeping the DFI P35 I ordered and keep the money saved for the video card upgrade.