I have build clusters, render farm and other types of super computers in one of my previous job.
Like they said, this is indeed expected. You have all kind of issue, bad cables, bad memory, etc. If you have 1% defect rate and you build a 1000 nodes system, that means 10 systems will have defect.
After that the fun start, try to find the source of the problem, trying to isolate it. It takes times and effort and the larger the cluster is, the harder it can be.
Render farm are most of the time easier since they just use the network and will crash by itself. A cluster have also the interconnect that can fail. You run codes on multiples nodes and it's not always clear where it fail. Sometime one node will crash because it received corrupted data from another nodes. Sometime it's the switch, the storage, etc. Way more parts to fail than a regular PC and trying to pin point a failure can sometime be really a pain in the ass and take days.
So to me, this article is more something to please the AMD bashing communities than anything else. I build both AMD/Intel systems and it's was not really much the CPU vendor that really effected defect rates. Larger cluster required more time to settle.
