Over the years I have seen quite a lot of defective PCI Express risers, but the recent boom in crypto mining and the demand for PCI-E Risers that use USB 3.0 cables has skyrocketed. Since these are being made in China because of the price and quite a lot of busnesses are already relying on producing these boards for moving away your video cards from the motherboard things are getting worse...
Quality control is almost non existent anymore and there are stupid mistakes being made in the production, mistakes and issues that can result in you getting expensive video cards and/or other hardware burned. It is good that most of the time there is no permanent damage being done by defective PCI-E extenders, they just don't work, but still the possibility is there to get things damaged.
What I'm seeing lately as a trend is regarding the soldering of components on the PCBs, itis really bad - either so little solder is being used that components are barey held in place and making electrical contact (some actually don't and as a result either don't work or break connection from time to time) or there is too much solder used that it is shorting multiple connections.
Usually it is not much of a deal in either case as it is more often on the data pins and the extender does noo function and with some soldering skills you can easily fix the issue youerself. However if it there is a problem with electrical contacts being shortened things might get a bit worse... so it is alway best to check first and then install the extender boards in a mining rigs!
If you have a question or want to add something, then please leave a comment below.