Originally posted by: Idontcare
Yeah I'm not asking whether increasing HT means increased L3$ or not, of course it is implied that raising one also raises the other...I was more just curious based on what you know of the architecture whether the increased HT itself is really going to contribute to IPC gains or whether it was more likely that the commensurate increases in L3$ speed would be the dominate contributor to IPC increases with AM3/DDR3 PHII's vs PHII's on AM2+/AM2.
I'm hoping I'm following your question correctly - I am not entirely certain of DDR3's gains over DDR2. I remember when DDR2 came out (PC4200?) , the first iterations came out with latencies and speeds that it really wasn't any faster than DDR-400 at the time. It was the headroom provided as the technology matured that started giving way to performance increases. I honestly don't know if DDR3 is/will follow the same pattern (to be honest, I haven't followed DDR3's development much at all - all I know is that it's supposed to be fast enough that AMD will be migrating from GDDR5 to DDR3 for video cards in the next iteration).
With that said, I've skipped a generation of AMD processors - and I honestly don't know if The Phenom II is bandwidth starved with DDR2 or not. If I would venture a guess, the faster cache and HT link itself (to ferry the data to the cache) will be more important performance-wise than DDR2/DDR3. With that said, in multi-threaded apps, I think the faster HT links and cache will make for a bit more performance with cross-core communication - especially since the Phenom II has a larger cache to deal with (more data in faster cache = less reliance on the memory bus speeds).
So in short - my opinion would be that the 11% increase in HT/Cache speed will mean more for the AM3 Denebs than DDR3 would (which would mean the AM3 Denebs in an AM2+ socket should perform better than the AM2+ Denebs do from day one by a few %).
There's so many variables (load types, etc) that I honestly would be lying if I could tell you with any certainty which means more to this CPU at this point. I am definitely no electronics engineer, but since we're talking apples-to-apples with merely a clock comparison, you can bet the AM3 version will be faster, but I doubt DDR3 will have a ton to do with it.