Prime95 is my gold standard for CPU and memory testing. Everything from desktops to HPC and clustered filesystems get a 24 hour “blend” of tests. If that passes without any instability or bit flips then we’re ready for production.
In my experience, LINPACK (at least the Intel MKL on GenuineIntel combination) is both quicker and more thorough in finding setups that are not actually stable/reliable.
I had memory stability issues which would immediatly show under Prime95 (less than 1 minute) but pass hours of Linpack.