That's the thing isn't it.
Whatever magical fixes they apply to 7 - even if it is in an attempt to massage it inline with 8 (if that's the magic bean theory), it may well be benefitting the Intel variant in anycase.
This 40-70% increase, can-not be in flat out performance. They have to be using numbers (if it comes to fruition) like nVidia use similar numbers with new graphic card drivers.
e.g. 40% increase in Batman.... erm that mean your 100fps now become 140fps - which doesn't happen. You probably get cores working 40% more efficientlty, which ends up as probably a 5% increase in overall performance.
Here I am trying to argue with you and you are thinking the same as me...I re-read your post I quoted previously and it makes a lot more sense now.
