Up to now, most sources stated the upcoming 22 nm replacement for Xeon E5 and Core i7 39XX to have 10 cores per die. Post IDF, a very credible source says it was 12 all the while, just the yields weren't sure of.
Well, now they are. Compared to the Sandy Bridge 32 nm E/EP part (there is no EX Sandy Bridge at all, remember) which has 8 cores and 20 MB L3 cache, and only 6 cores and 15 MB L3 in the crippled desktop version, there's now much more in its plug-compatible follow-on.
The original estimate for the Ivy Bridge E/EP die was 10 cores and 25 MB L3 cache, again keeping the same 2.5 MB L3 per core proportion as the Sandy Bridge EP die. However, the sweaty blue blooded man who we befriended at IDF, had this to say recently after the show: there were 12 cores on the die all the while, but they weren't sure how they yields would go, that's where the 10 core presentations came about. Now, the yields look good, and there will definitely be full 12 core / 30 MB L3 cache bins available, even at high frequencies for the workstation use – but at a premium price, of course.
If such a part runs at, say, 3.2 GHz inside the 150W TDP envelope, it'd give you well above 300 GFLOPs in peak DP FP per socket, providing a 600++ GFLOPs DP FP dual socket workstation. Do remember that Intel's workstation CPU warranties cover reasonable work day use, not 24-hour day, 365-a-year use like server CPU's though. As for the gaming CPU SKUs, let's hope at least 8 out of 12 cores will be enabled.