The Blockchaindriver has a bug. Open the AMD Settings and change that:

Make it to max and apply. Then start the miner. I use Cast XMR and my Vegas are between 1920-1960 H/s
i didn't install amd settings so I used that disable enable trick
i am using the xmr aeon stak version. not sure if that changes anything
https://github.com/IndeedMiners/xmr-aeon-stak/releasesI had the same Problem that i never used the AMD Software and my hashrate was just 1400 H/s. So I install it and it helped me a lot. Also i would try Cast XMR