Choosing the best GPU riser for your rig.
There are many variations of GPU risers out there, some are better then others, but a few can be potential hazardous depending on your situation.
-PICTURE OF RIBBON CABLE-
Ribbon cables are flat and wide cables with a PCI-E plug on one end for your motherboard and a slot that attaches to your GPU on the other. Not many people still use ribbon cables, they had a lot of drawbacks compared to the more recent risers. First off the connectors are usually flimsy, the ribbon cables are usually very small making it hard to space your GPUs properly. And worst off you had to use a different cable if you wanted to use 1x PCI-E slot and 16x PCI-E slot. I would not recommended spending any money on these and saving yourself a headache by purchasing a GPU riser.
SATA Powered Risers
-Pic of riser-
Sata-powered risers are usually the cheapest GPU risers on the market and for good reason. Sata connectors can only handle a max power draw of 54 watts. Way too little for your average GTX 1070 or RX 580. A lot of people tend to buy these or the Molex variety because they are a few dollars cheaper which adds up when you are buying risers for an entire rig, but the risk is not worth it. Many horror stories have popped up on places like bitcointalk of people seeing or smelling smoke and noticing the risers/gpus are burnt. Most of the time the culprit was the sata riser being pushed passed its capacity and melting. So stay away from these unless you are using a RX550 or something similar.
As a side note do not daisy chain with these risers. Daisy chain is putting 2 or more GPU risers on the same cable. A lot of Standard PSUs come with cables that have multiple SATA/Molex power connectors but only use one for maximum safety.
Molex Powered Risers
Molex powered risers are o.k to use with most Mid-Grade GPUs or High-Grade GPUs that are being power limited. Their price point is good and usually are priced closer to SATA powered risers. Now comes the confusing part, a lot of sellers will usually give you an attachment that looks like:
This attachment plugs into the molex part of your riser and then you connect your SATA connector from your power supply to the other end. This kills the whole purpose of using molex powered riser.. Just attach the molex connector from your power supply directly into the riser, just skip the entire attachment entirely. I feel like these were given because a typical ATX PSU has an abundance of SATA connectors helping you ensure you can use six GPUs on one power supply but is the risk worth it?
In all honesty I have used these risers when I first started without too much trouble. I had 2 1070s or 1080ti daisy chained on one molex cable, but they were Power Limited to 70% using MSI afterburner. So at the end of the day it really comes down to how you are running your GPUs, if you are going to OC them and use as much power as possible I would skip these. If you are going to power limit your GPUs or you have some lower end GPUs then these are perfectly safe and help save days of ROI in the long run.
6 Pin PCI-E Risers