Is it possible to use a PCI-e 2.1 x16 graphics card in a pci-e 2.0 x16 video card slot, and what are the compy?

PCIe 2.1 x16 is backwards compatible with PCIe 2.0 x16. So to answer your question, yes.|||hi zane

yes no problem.... you can install the newer pci-express v2.1 cards in a v2.0 port without any problems.... they are all backwards compatible so you can actually install a first generation pci-express v1.0 graphics card in a pci-express v2.0 slot....

the only downside though is if you use a v2.1 graphics card in the v2.0 slot then it will only run at the maximum speed associated with the v2.0 slot ( 8 GB/s (64 Gbit/s) ).... and the same would apply if you ran a v2.1 graphics card in a 1st generation v1.0 slot... even though its designed to run at the v2.1 speed ( which is actually the same speed as the v2.0 ) the card would only run at the v1.0 speed which is 4 GB/s (32 Gbit/s)

however zane dont get these speeds mixed up with the memory bandwidth and clock speed on the actual card..... if a card has a 4000mhz ddr effective memory clock speed it will run at that speed in all pci-express x16 slot versions.... and the same applies to the core clock speed and shader clock.... these are specifications of the card and not the pci-express slot

thats why i dont get too picky when it comes to the pci-express slot... obviously i would buy a motherboard with the most up to date pci-express slot however if there was a board with dual pci-express x16 (v2.0) slots and another with a single pci-express (v2.1) i would go with the dual slots running at v2.0.... and i would also look to see how many sata ports it had and the locations of power connectors.....

so i wouldnt worry.... you will have no problems using your v2.1 pci-express x16 graphics card in your v2.0 slot..... and since both the v2.0 and v2.1 pci-express slots have the same per-lane throughput you wont even lose any speed.... the only time you would lose throughput is if you use the v2.1 or v2.0 graphics card in a older pci-express v1.0 slot

i hope this has helped zane,however any questions let me know

good luck mate !|||Every motherboard with a PCI-E x16 slot is compatible with every PCI-E video card.