Its getting close to 4 years I have been mining with 3 rigs of 8 cards (8 x 1070, 8 x 1070ti, 8 x 1070ti). They run 24/7 in a smallish room (2.4 x 3 metres), sitting on old carpet in an old flat. In an Australian summer, ambient can go north of 40 degrees Celsius. Basically, hell on earth for mining rigs. Fans began to fail after 6 months due to the dust, solved by replacing the sleeve bearings with double ball bearings. But the biggest problem is heat. Remarkably, the only issues I have had besides the fans is the pcie splitters melting.
Each rig has a silverstone 1500ti power supply rated to handle 150 watts from each of the 8 pcie outputs. Each output supplies one card through a pcie splitter, (one for the riser and one for the card) Each card is limited to around 120 watts so there should be no problem with this arrangement.
However over time I discovered some of the pcie splitter connectors began to overheat to the point of wires melting/breaking. Some were fine but many were too hot to touch even if they were still working. The wires were cool, it was just the splitter connector that was failing. Clearly the dusty hot environment was causing issues. So I implemented a final solution of cutting off the connectors and soldering them on. That's 24 cables I had to butcher so it took a while.
That has entirely solved the issue with the bonus of saving around 40 watts of power per rig. That presumably was how much heat was being wasted in the connector.
Connectors are always going to be a weak spot, the fewer the better and those you have, you should check occasionally. If they're getting hot, do something about it!
