http://www.theverge.com/2012/3/13/2867224/new-ipad-geekbench-test-1GB-RAM
Yea i must admit i was dissapointed to see that, thought they would have inceased it to 1.2-1.5ghz?.. perhaps they are keeping it low to make the new A6 look even better!! we all know a 2.0ghz dual A15 would easilly be 3x the performance of the A5X...probably more!
I think it more points to them adding the 2 extra GPU cores by increasing the die size, and still being on the same process technology hence no increase in any clocks.