Yes you beat me too it. Fill rate suggests a slight increase in the clock over ipad3, probably up from 250mhz to 280mhz. Overall gl2.5 off screen results give a x1.8 improvement over the ipad3.
I'll have to take back what I said about A6X. Graphics die size. 544 has double the processing power of 543 and also includes dx compliance, so relative die size will increase. I did say that apple appear not at all bothered about die size. We'll know more when chipworks do their usual die breakdown over the next few days.
Saw that, seen an article that suggested that the graphics in that core would be SGX. I can't link to it as its not for public consumption, and anyhow I would not have much faith in the suggestion. However it is interesting that your article does state a change of gpu core for power reasons.