it was or is to be said that Ivy will net you about 15% more performance than Sandy.
but right now Ivy is a higher power consumption (TDP) and runs higher temps than first predicted.
it's not quite going to be as big as the AMD Bulldozer disappointment/fiasco but early reports are very very disturbing.
so untrue. everyone is throwing around that 15 percent number. the graphs i looked at were closer to 5 percent.