I have two reasons for my previous post, friend:
1) indeed, some external factors can impacts benchmarks, specially for such small amounts. And that can be as simple as a single software installation or upgrade, or even a windows update.
2) 100 less points on a synthetic benchmark like 3DMark, which always does the same thing using the same algorithms, exactly the same way, can be due to the driver dealing with things a bit less nicely for 3DMark but much better for everything else, which is real applications like games. This happened a lot of times before.
So yeah, I'm still amazed when veterans here are alarmed by a 100 point decrease in 3DMark score. Would you say 1000+ points, then yes, there's most likely something wrong.
PS: and if you wonder why I took a 290x, it's because where I work, I pay them less than the random customer would pay a 290
On topic, those drivers seem to run smooth like silk on my 290x. I get no significant (!) performance increase or decrease, but I get no more artifacts on the desktop using Firefox dual screen and moving browser windows around like I was getting with 13.3. No crash or bug noticed yet, neither with 3D gaming (WoW, EQNL, GW2) nor with Blu-Ray playback (PDVD13).