K404s scores on the first 3 tests scores far better then you, just in nature you pOwn him hard (with far lower clocks) Tweaking via OS, nah.. though kuddos you worked hard to discover it...
Rebench eg on XP... and see the difference in subtests... In fact it's not your fault each run is bugged, though as listed above there are discrepancies in your score outcome. Some tests can't score higher than others, but you will discover that quickly when comparing with other scores (see which tests crap out...)
Drivers can boost performance, but that doesn't mean ( especially in 3Dmark03 which is very GPU dependant ) that you can surpass guys that run eg 25% faster clocks with decent CPU speeds... and your nature score goes close to ...% faster than anyone elses... doesn't seem logic does it...
if you fail to understand ask your dad why that chair is called a chair... he will tell you son, it's like that...
I hardly overlook scores, but when I have a similar card and look at the scores and see something weird, then it's normal it will be rectified...