You should run the cuda 11.5 build for the best speed.

hashrate bugs in 1.28

When a solution was found,  it exited the solver immediately without scanning the whole range of nonces, but the full hashrate was added. This is caused a inflated hashrate. Worse on on low difficulty.
An index bug sometimes caused hash to be added to the wrong gpu, so if you run with a good gpu and a poor gpu in the rig, the poor gpu's hashrate could be inflated.

in v1.36 we have increased the number of samples in the average hashrate, so you should run for a longer period of time.
We reduced the default intensity to reduce the stale shares.

Poolside the cuda_11_5 1.36 should be better.