Enter the Dragon: AMD AM3 6-core desktop arriving in 2010

[ajaidev]

OK sorry ajaidev, but I think you don't really understand prefetching.

Prefetching is a method to predict which data the CPU will be requesting in the future based on its access patterns in the past. Simple prefetching mechanisms are next-line (prefetch sequential pieces of memory after a load/store req), stride-based (determine if there's a constant stride (eg 0, 4, 8, 12, 16...) and prefetch based off off the stride), and target-based (keep track of branches that cause misses).

Generally speaking, prefetch requests are the lowest priority accesses to memory, meaning that it will not "slow down the work that is done". However, there can be cases where a too-aggressive prefetching mechanism can evict cache lines that will be used in the future. For most applications, this problem is avoided through application profiling and tuning of the prefetching algorithm.

As a general rule of thumb, prefetching can improve the performance of most applications regardless of the amount of bandwidth available and even with "low latency" DDR. Remember that accessing "low latency" DDR3 is still ~50-70ns round trip, which translates to at least 150 cycles at 3GHz. Compare this to even the slowest 30 cycle L3. The fact that prefetching is even done from L3 -> L2 or L2 -> L1 (move items from lower level caches to higher level caches), which saves a "mere" 10 or so cycles, should clue you in on how important it is.

Actually that's what i said i was talking about the time delay it would take for a nahelem arc to prefetching from L3 "L3->L2 and then L2->L1" as compared to K10's L2 "L2->L1"

I never said memory prefetching is better than cache prefetching !!!

2,8-3,0GHz seems reasonable on 45nm within a 125W TDP ratio. Remember that AMD will release a new stepping later this year so I think 125W will be possible for such "high" clocks

There are also rumors of 32nm desktop parts based on K10.5 but I have no clue if those are true or not...

Even a 3Ghz 6 core with 140w TDP is great in my head. 32nm desktop parts do u mean the AMD LIano if AMD does release a K10.5 core at 32nm in 2011 they are out of their minds. Sandy bridge will totally kill them.