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Technology Stocks : Advanced Micro Devices - Moderated (AMD)

AMD 214.11

+3.9%

Nov 26 3:59 PM EST

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To: Joe NYC who wrote (76466)	4/4/2002 12:15:33 PM
From: pgerassi	Read Replies (1) of 275872

Dear Joe: Why do you think that Clawhammer will not have enough bandwidth to compete against NW? It may have less theoretical bandwidth, but that is not what CPUs actually get from the memory channel. Look at the memory bandwidth found by Sisoft Sandra for 2.4GHz P4 between PC2100 and dual PC800. PC2100 got 2GB/sec and PC800 got 2.4GB/sec, 75% of the theoretical bandwidth. Clawhammer will run on PC2700 and probably get 2.6GB/sec to PC800's 2.4GB/sec. Even dual PC1066's 4.2GB/sec will get only 3.15GB/sec in a real box which could be matched by a single PC3200 channel for Clawhammer. Now the actual bandwidth is even less than this due to latency. Other than cache tests, which are not typically done any more, there is no standard benchmark to find this very important number out. Yet the efficacy of decrease the CAS setting has shown that even a 1 cycle decrease in latency yields to significant performance boosts. Going from CAS3 to CAS2 is more than equivalent to boosting bandwidth by 33% overall. An onchip memory controller has been shown to be the equivalent to decreasing the latency by 2 cycles. If you look at the above, a PC2700 on chip channel is the equivalent to a PC3600 with a single cycle and PC4500 with two. Dual PC800 is slower than off chip PC2700 and it would take dual PC900 to match. Thus one cycle decrease would match dual PC1200 and two matches dual PC1500. In either case, a single on chip PC2700 channel outruns off chip either dual PC1066 or dual PC2100 in real world benchmarks. You seem to look at the off the paper based comparisons without taking a look at experimental based comparisons which trump the former. On paper Itanium was great, experimentally it was a loser and undesirable. Also what are you calling a Sledgehammer? Is it a dual core or single core in your definition? A single core 1MB L2 would be about 124mm2 and dual core 1MB L2 each 224mm2 both at 0.13u SOI rules. Single core is smaller than NW and even on paper, would shred Prescott in bandwidth, latency and sheer performance. As to Durons, you seem to forget that there is different markets mostly abroad. There Durons are selling. Since AMD is selling WW, you need to consider where even $20 is a big amount. This is where those integrated MBs with Durons sell. Where a $300 system is better than none at all. At $50, Durons break even on Fab 25's 0.18u wafers and are in more demand than 0.18u flash. Also many Durons are sold into the mobile market. This is where Appaloosa makes sense. It will be lower power and higher performance. Let 0.18u Al Durons sell into that low end overseas market keeping Fab 25 profitable till flash picks up, but sell Appa's into the mobile market where Durons have significant marketshare (and higher than $100 ASPs). Pete

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