Why not just use a lower PCI Express version? You might lose some speed but it will be backwards compatible with the lower clocks.

Actually, both Xilinx and Altera offer PCIe v3.0 blocks on their high end FPGAs (Virtex 7/Kintex 7 and Arria 10/Stratix V).

Yes, of course, but this is already a little bit beyond the DIY budget I hoped for.

I made a Kintex 7 board in my homemade reflow oven and 2/2 worked. I had more trouble with the QFN I used for the core power supply than the FPGA.

I'm more concerned about a budget here than a reflow. Cheapest Kintex 7 part is around £90.

Ah I missed the part about DIY - that sucks though.

You seem to be familiar with PCIe 2 though, so now I'm wondering - is there a chip that could convert the 1x PCIe 3 lane into a 2x or 4x PCIe 2 set of lanes? Also, worst case, if you really wanted to use this chip, couldn't you just use the chip with PCIe 2 (albeit slower, but I think revisions of PCIe are supposed to be cross compatible)?

> is there a chip that could convert the 1x PCIe 3 lane into a 2x or 4x PCIe 2 set of lanes?

Never heard of such a thing, although it might have been really useful.

> couldn't you just use the chip with PCIe 2

Did not even think of this option, sounds interesting. I guess we should wait for the datasheet for this chip to be sure.