can a radeon 5670 reach full speed on pcie x16

Title. Will it be able to achieve faster performance on a PCIE 2 card compared to being on a 16x card or will the perfomance be too evenly matched to tell a significant difference?

 

X16 refers primarily to the motherboard slot, not the card. And the 2, as in PCIe 2.0, refers to the whole PCIe protocol. In other words, you don't compare PCIe 2.0 to X16. That is like comparing a new Porsche to a highway.

So if the card is a newer model and supports 2.0, and the motherboard is a newer model and supports 2.0, then the card, which still goes in a x16 slot regardless, will, in theory, reach maximum performance for 2.0.

If you buy a new 2.0 card and install it in an older motherboard that only supports 1.0, you still install it in a x16 slot and it will still work as a 2.0 is backwards compatible. And a 1.0 card will work in a 2.0 slot too.