I've been going bonkers. When I first ran my GPU the day I got it on the 456.51 driver with barely overclocking anything my GPU score in firestrike was near 45k.After updating the driver and pushing my OC limits to the max I was barely breaking 40k. I updated to the latest EVGA higher power target bios and everything still barely scratching 40k running +100 core, max voltag and +500 mem. I just reset to the prior driver and with no OC at all, I hit 43.3k. On my last FS run using 456.51 I was back at almost 45k, my last run on the newer driver was 40.6k The last run on the newer driver was fully tuned pulling max power under load. The last run on the old driver was way higher with a much more chilled out OC.
 
What is up with this? 
FS Score on 456.51-> https://www.3dmark.com/fs/23792592
FS Score on 456.71 -> https://www.3dmark.com/fs/23792431 
 
Notice the boost and mem clocks are very similar on these 2 runs. Yet the 456.51 run is over 3000 higher in score.

I noticed a 6% difference in CPU performance - that a bit outside margin of error.

I'd suggest you try a run on both sets of drivers with a clean boot (nothing extraneous running). You'll likely find that there was something in the background causing that disparity.

Also, set any overclocks and exit out of PX1. It actually causes a big loss of score when it's running.

Hey, at least you know!

icue, synapse ect they all are detrimental if running while benching. Nice scores and glad you figured out the difference.
 
I personally thought the newest driver would be worse for performance but honestly I get alot of what appears to be RNG crashes with 456.38 on the 3090fe and 456.71 does not appear to nurf the 3090 idk though... More testing to be done when my FTW3 Ultra arrives on thurs.