2 x16 pcie vs 2 x8 pcie

kurby88

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Oct 20, 2010
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First, I am an avid user of 3 monitors (thinking of upgrading to 6 at some point in the next year or two). My most demanding uses are eyefinity gaming with semi-modern games.

After reviewing as much of the information as I could find I am curious if anyone could point me to a more modern (2013 with current high end graphics cards: 7xxx and GTX 7xx) benchmark showing the difference between sli/xfire with duel x16 PCIe 3.0 and duel x8 PCIe 3.0 motherboards. Most of the information I have found seems to date between 2006 and 2011.

Additionally, with graphics demands increasing... will the smaller bandwidth provided with 2 PCIe x8 slots start to bottle neck 3+ monitor display setups? aka... will the next generation or two of video cards hit a point of seeing a huge lean to duel PCIe x16 3.0 slots over 2 PCIe 3.0 x8s?

Or maybe this will all be resolved with a higher bandwidth technology... PCIe 4.0/ PCIe x32 slots perhaps? (both of these are random thoughts and not based on any released information for either technology ever existing).
 
at about the speed of a 7950/760 you start to see a tiny little bottlenecking at pci-e 2.0 x8... in the realm of 2% lost... for comparison 2 titans in SLi on pci-e 2.0x8 slots will lost around 6%-8%, which is about the same amount a 690 or 7990 will lost in quad xfire/sli with another card on a pci-e2.0x8 slot. in short it won't really hinder you in any real way... a little bit but not enough to matter.

as a sidenote, this is why pci-e 2.0 x16 is still far more bandwidth then any gpu could use... and why i call pci-e 3.0 a marketing gimick... i mean there isn't a card today that comes CLOSE to maxing a pci-e 2.0 x16 slot, so that means pci-e 3.0 is REALLY pointless. I mean many modern gpus don't even max out a pci-e 1.0 x16 slot