When Chrome browser is running on your PC, it prevents the
miner from reaching its full speed (due to resources occupied
by Chrome on gpu). Thus close it before measuring mining speed.

The sol/s change all the time due to the statistical nature of the
equihash algorithm. You may get different results each minute. Each
job sent by the pool has different number of solutions in it. Thus
compare performance of different programs over time.

You should expect the reported sol/s to change about 10% to 20 % all the time.
This behaviour doesn't depend on the implementation, its in the core of equihash.