On both version - v9.0 and v9.3 I have the same cpu usage on (latest G4560 3.5 GHz) about 1-2% overall cpu usage of whole system
If you are sure that the reason is the miner, not your pool or internet connection, you can create two log files and PM them, I will compare them.
I can confirm that actual hashrate(current hashrate) is a bit lower on 9.3.My average hashrate dropped with 10 since I updated to 9.3 from 9.1