Justin: There would be no difference in performance if it was running on a PCI-E 2.0 interface. Even with Penryn and high speed DDR3 memory...The performance would improve obviously..But it would be due to the newer processor and faster ram. Not the PCI-E 2.0 interface. you would get the same performance popping that new processor, ram, and 8800 gt on a PCI-E 1.1 board.
Went back and read most the posts I skipped....Regarding PCI-E 2.0
There will be no difference what so ever placing a 8800 GT in a PCi-E 2.0 compatible board. You will see likely the same exact performance. The advantage of PCI-E 2.0 which most of us know, but I'll state for those who don't, is the doubling in bandwidth and watts supplied from the slot. PCI-E 1.1 has 2.5 GT (Gigatransfer, 2.5 GT = 8 gb) of bandwidth with 75 watts of power running through the slot. With PCI-E 2.0, bandwidth has been doubled to 5 GT (16gb) with a 150 watt rating. Therefore eliminating the need to add a power connector for certain cards.
In terms of performance...There will be no difference ATM. The sole reason for PCI-E 2.0 is obviously for future use. Once cards can exceed the 2.5 gt barrier it will be needed. ATM it's more a matter of adopting the specification to current technology to prepare to break that 2.5 gt limit. There are currently no graphics cards capable of surpassing the 2.5 gt barrier. So therefore you won't see any difference. Just cause the bandwidth has been doubled from 2.5 to 5 gt..Doesn't mean you'll get a performance boost. It's up to the actual hardware being capable to output that much bandwidth....which current graphics cards can not do. Therefore, It's a false statement to think you'll obtain a performance boost from going to PCI-E 2.0 from 1.1...Just cause you have the ability to transfer more bandwidth means nothing if the cards we have aren't capable yet to do so.
As I stated before, it's just adopting the technology to help when the barrier is met. This way, we won't have to dish out more money in order to get a motherboard to support these new cards when they are released. Having a faster processor, faster ddr3 modules...It doesn't do anything for the bandwidth transfer via the PCI-E 1.1/2.0 spec. (It only does if your processor is bottlenecking your system. You obviously need a decent processor).
No rig atm will benefit from PCI-E 2.0....The only way I can see a benefit is in terms of power since you can eliminate the molex connector on certain cards for PCI-E 2.0 spec. So overalll, Just cause your board has the ability to transfer 16 GB via the PCI-E 2.0 slots compared to PCI-E 1.1's 8 gb...Means nothing if the hardware isn't capable of utilizing that extra bandwidth....Current graphisc cards can't break the PCI-E 1.1 barrier...But I expect that to change within the next 2 years....hopefully with the new high ends...But we'll have to wait and see.