Synthetic benchmarks – CoreMark, Stream, Membench
First of all, I will focus on some synthetic benchmark results. The first benchmark is CoreMark, which measure the CPU performance. While it depend primarily on the target CPU and I don't expect its results to be greatly influenced by the distribution used, please remember that it was compiled against the distribution-specific libc stack and compiler.
As expected, we has vastly similar results, with Red Hat pulling slightly ahead.
How about memory bandwidth? Lets examine it by using STREAM...
... and Membench
Again we see very similar results, with Debian showing some very small advantages in certain tests.
So we can conclude that, as expected, the performance of the two Linux distributions in theoretical test is the same. This means that, from a CPU and memory standpoint, there are not obviously wrong things in (only) one of the two contenders.