One possibility is the CUDALucas instance or some other load was still running on the same GPU when gpuowl was timed. If the user Magellan3s would run gpuowl in background, while doing top and lsgpu in foreground, and share results of that, it might be informative. (But it takes 2 LL versus ~1.01 PRP with proof, so CUDALucas is at more than triple runtime disadvantage per exponent completion.)

The ratio (post 12 cudalucas 642.3usec/it in LL) / (post 5 gpuowl 389 usec/it in PRP) ~ 1.65 is about what we would expect based on numerous comparative benchmarks on numerous GPU models by multiple users. The commonality in the anomalously slow A100 timings is apparently with a user or test methodology or gpuowl version. post 4 gpuowl 1050 usec, post 12 gpuowl 1036 usec, is a whopping ~2.7:1 speed difference. Why is CUDALucas using a larger FFT but considerably faster than GPUowl? | Date Time | Test Num Iter Residue | FFT Error ms/It Time | ETA Done |

You may experience a small delay on 1st startup to due to Just-in-Time Compilation

Opencl benchmark headless