How many pcie lanes needed per card?

[300c]

I currently have a selection of older Nvidia 1080ti's and AMD RX580's. They were miners but I am wondering if a different card will get me a better watt per hash. Each card is connected via a single PCIE lane to the cpu. I need to know if this will work, or this is what is causing my slow hash rates?

I'm not looking to do this long term, but I have been at hashing long enough to know the real cost is electricity. I need to crack some 7zip files so -m 11600, hash rates are low I think for this. A rig is running 8 cards, each card via a single pcie lane, unless I change out the motherboards and risers. A nvidia 1060 gets 3200h/s, 1080ti gets 6400 h/s both for about 132 watts per card.

Suggestions for cards vs watts would be appreciated. 
Thanks,

[cpu_pirate]

This is simple, you need more power. The single lane is fine but you cant tune hashcat like you do mining. Open the power up on the card and let it work.

Alternatively you can test this by placing a single 1080Ti into an 8x or 16x slot with a couple of the other cards disconnected ( most mining MOBO's have at least 1 x16 slot) and do a benchmark or test the hashrate, but the power is the limit here.

[300c]

My mining boards are all x16 slots but they only have a single pcie lane to them. Early on I tried riser cards and various motherboards, it was an unpleasant experience. If you look up BTC-37 mining motherboard on ebay you can see what I am using. I am looking for a computer to test with. This will suck if each card will actually need a full x16.