What do you mean by higher ? what were the scores and did you run it more than once ? Differant drivers and just being able to do a certain test better due to more advanced SP's in the newer card would make enough differance to sway the scores a couple of hundred either way.
Heck if i run my card twice its a bit out each time. Things running in the background could even cause it.
In short unless its a big differance say 500 or more i would say there is no meaningful differance.
Exactly technically why its scored higher, I dont know if you really want to know you would need to get the full test and compare where the cards score differantly in each test.
Well as i said that amount of difference doesn't amount to much but it would seem by looking at the links that its the SM2 score where the difference is. I would put that down to more efficient throughput through the architecture, it simply handles SM2 better than the 4890.
I'm not saying that's 100% definitely why but that's the way it reads to me.