[colanderman]

Presumably disable. They are enabled by default, and the suggested use is to disable for more reliable benchmarking.

[x0x0]

Unless you plan to run with these disabled, how would disabling them during benchmarking possibly improve the relevance of the benchmarks? And if the benchmarks aren't relevant, why benchmark?

[colanderman]

If, e.g., you're trying to benchmark the memory itself, and not the processor's prefetch algorithm.