Disabling the GC means your benchmark is worthless.

1. Valid GC during execution: you are removing an actual factor;

2. "Invalid" i.e. unrelated GC during execution: your benchmark is too narrow in scope.

It depends on what you're benchmarking. If you're benching wall time, then yes, you need to have GC on, and you need to do a ridiculous number of iterations to average out GC runtimes. You also need to invoke the GC before you begin your benchmark; doing a collection pass early in the benchmark for all the objects created on startup/setup skews the benchmark.

Separate benchmarks should be conducted for execution speed (CPU time) and garbage generation. Saying "X is faster than Y" tends to suggest a CPU time benchmark. "X is faster than Y with W delta garbage and Z delta less time spent in GC" suggests a proper wall time benchmark.

On the other hand, 10k+ iterations likely isn't anything you normally experience, and may incur abnormal GC cost due to the sheer number. Though that's typically detectable by doing multiple sizes of tests.