Re: PCIE gen 4 will it have an effect in crypto mining?
The PCI-E extenders can run at PCIE 1.0 X1 with no hashrate drop. What makes you think that you will benefit from PCIE 4.0? 
I am not 100% sure this is correct but I remember back in late 2016 early 2017 when ZEC was first released and Claymore released a miner for it, the GPUs which used the x16 slot were faster than x8 which was faster than x4 and x1. And the conclusion drawn was that Claymore coded the algo to do some compute with the CPU for every cycle.
I think the reason why Pcie 1.0 X1 has no drop than a Pcie 3.0 x16 slot is because it doesn't communicate with the CPU too frequently. So the Pcie 4.0 probably wouldn't have any boosts compared to Pcie 3.0 currently out.
However with gaming is very different because the GPU communicates much more frequently with the CPU and maybe for gaming it might have an effect.
I am well aware in the gaming side of things and that most of GPUs right now cannot even maximize the PCIE gen 3 bandwith. What I am here for is that your thoughts in the future of this technogy. Will developers take advantage of it to make a new algorithm that uses such transfer speeds much like in raid configuration? As in data computing in data center such speeds will benefit from such tech.