To: Pravin Kamdar who wrote (11507 ) 10/5/2000 9:44:07 AM From: pgerassi Respond to of 275872 Dear Pravin: Given that Intel likes to tout P4 MHz advantage (ship 1.5 GHz in Nov 00), why doesn't AMD point to Kyrotech 1.6 GHz (Tbird?) in Nov 00? Since a Kyrotech solution adds about $300 to $500 and i850 plus 256 MB of RDRAM costs about as much over AMD 760 plus 256MB of DDR PC2100, the game would be equal at cost (assuming that the retail price of 1.5 GHz P4 is the same as 1.2 GHz Tbird) but, IMHO Tbird would just about destroy P4 in all but a very few benchmarks. BTW, I read some speculation on the non-moderated thread that P4 (internally named P68) was just an improved and longer pipelined double speed back end (xx8 (2nd try? or was P3, xx7?)) with a P3 decoder unit at normal speed (P6). If this is true, and looking at the diagrams for the pipeline stages for x86 decode and functions blocks in Intel IDF presentation it appears that it could be true, then any multitasking code or real time apps, where heavy context switching occurs, will cause the P4 to run the same as a P3 at half the clock rate of the P4. Thus, the benchmarks testing a 1.5 GHz P4 using heavy server type loads, would run like a P3 at 750 MHz (probably somewhat faster due to FSB bandwidth and short bursts in tight loops occur (the best code for P4)). Given the P4 benchmarks leaked to JC, it appears that the trace cache, doubled pipeline, and QDR FSB, gives a 40% improvment to overall throughput in normal real world office loads, a 90% improvement to loads with tight loops that work on massive data, and a 100% improvement on loads that can take advantage of SSE2 over x87 to the original speed P3. Thus, a QADG (quick and dirty guess), would put a 1.5 GHz P4 at a similar performance level to a 650 MHz Tbird on server loads, a 1 GHz Tbird on office loads, a 1.2 GHz Tbird on tight loop loads, and a 1.33 GHz Tbird on SSE2 loads. Without knowing the amount of performance improvement Mustang derived CPUs have over Tbird derived CPUs, it is harder to figure how P4 would compare to Mustang/Palomino/Morgan. I assume that they would outperform Tbird by at least 5% (if not more (WAG)). Thus the entire Palomino line could be higher in performance than the top P4 over all these type of loads. The only loads for which P4 would come on top, would be any load that does lots of prefetchable data movement where the FSB is the bottleneck. Pete