C.A.M. (Clever Access Memory) performance

I’m testing the alleged advantace in hashrate performance and shares per minute with CAM enabled in BIOS (ASRock mainboard, full AMD rig), very small improvement if any (same rig and pool with CAM enabled/disabled). I see a little higher average boost in shares for the first 30 minutes but it’s not stable as time goes on, while hashrate doesn’t seem to change.

Has anyone verified a real improvement with CAM enabled?