Yeah your memory clock is beastly, but I might try and lower the memory clock to around 4050/8100 and see if that gives you more room to push the core higher. Its been noted that core clock does more for your score so you might pick up some points. As for the CPU speed reading it always lists...
It looks like you need to turn on the Tessellation setting and set it to extreme for it to compare to the scores here. Also, a screenshot (F12) is required in the benchmark to be listed. Stock clocks should score about 1300 with the proper benchmark settings.
I used a custom vbios to extend my TDP and voltage limits to nvidia hardware limit on the G1 970. (Hard limit is around 1.31v) Fans on my case were throttled to max. In the end I managed to gain a few extra points by sacrificing some memory clock for core.
I've been working with my G1 980...
I used this debacle with the 970 misinformation to facilitate a "Step-Up", if you will, to a 980
EVGA GTX 980 SC ACX2.0
Im eyeing 2K but I spent a solid 2 hours and I don't think it'll happen without more voltage. *edit -via hardmod
Based on others Id say thats in the 1520-1570 range. Your mem clock is great, but the core clock speed has the greatest effect. 1530mhz would put you in this range based on the charts on page one.
You might try finding out if you are reaching TDP limits, in which case sacrificing mem clock...