• Two integer clusters share fetch and decode logic but have their own dedicated Instruction and Data cache
• Integer clusters can not be shared between threads: integer cores act like a Chip Multi Processing (CMP) CPU.
• The extra integer core (schedulers, D-cache and pipelines) adds only 5% die space
• L1-caches are similar to Barcelona/Shanghai (64 KB 2-way? Not confirmed)
• Up to 4 modules share a L3-cache and Northbridge
• Two times 4 Bulldozer modules (2 x 8 "cores" or 16 cores) are about 60 to 80% faster than the twelve core Opteron 6100 CPU in SPECInt_rate.
http://it.anandtech.com/IT/showdoc.aspx?i=3681&p=3

very interesting article, who was asking about L1 instruction and CMP related info. Lastly SPECInt_rate hehe i am too tired to use the calculator some one put that percentages in numerical value.