you not after the extension cables your after whats called a pci-e x1 to pci-e x16 its a full x16slot connecting to a little x1 slot
https://www.bitmit.net/en/item/16581-pci-express-x1-to-pci-express-x16-adapter-new-free-shipping
https://www.bitmit.net/en/item/16581-pci-express-x1-to-pci-express-x16-adapter-new-free-shipping
1x cables are perfectly fine, you just have to cut off the plastic at the back end. A 16x > 1x cable is nothing else than 1x cable with a 16 connector rather than 1x one of the female side, no extra lanes or anything is actually connected. Like someone else said tho, you will probably need to short the detection pins as well.
Thats what I needed to know. But I havent seen it written any where. Thank You.
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