Does it matter what kind of riser cables I order?
Or will any x1 to x16 pcie riser cables work as good?
I use 6-pin PCI-E risers. Three thicker wires that are designed to spread a higher 12V load instead of two used by molex and sata connectors. The 6-pin risers also use four capacitors for a more stable current flow compared to the three used by the molex and sata risers. The good ones also come with a voltage regulator to prevent spikes. Here is a good overview of the different riser types:
https://www.youtube.com/watch?v=MxQM8MRGUWs
It's also a good idea to order twice as many risers as you think you will need. Nothing worse than being stuck with a card idle and waiting for risers to arrive.
These would be good right?
https://www.amazon.co.uk/YIKESHU-PCI-E-Powered-Adapter-Extension/dp/B071NMZSZ4/ref=sr_1_2?ie=UTF8&qid=1496940375&sr=8-2&keywords=pci-e+riser+6+pin
I like the push-pin type risers.
https://www.amazon.co.uk/Kyerivs-PCI-E-Powered-Adapter-Extension/dp/B06ZYCRX7B
They seem to latch on the card more securely than the slider type.