Rambus blows DDR into weeds

Bill Henning's groovy new MemTach memory benchmark described here has produced some initial results that appear to be good news for DDR SDRAM performance here, showing a commendable 41 per cent performance boost for PC2100 DDR memory over good old PC133. But our initial tests using our reference 1.7GHz P4 system equipped with 512Mb of PC800 Rambus RDRAM show that DDR has a very long way to go before it can mount a genuine challenge for the memory performance crown. The Sum Double test shows DDR scoring 41.1 per cent better than PC133, but Rambus manages a 63.5 per cent improvement - or almost 16 per cent better than DDR. Then things get very bad indeed for DDR. In the Sum Int test, PC2100 scores a modest three percent more than PC133. RDRAM is a rather immodest 81.4 per cent better and a stonking 76 per cent up on DDR. Check out the table below for details. These tests are memory bandwidth bound; processor speed is largely irrelevant (above a certain minimum level). In these tests; FSB speed and memory speed dominate.

MemTach 0.89	PC133	PC2100	PC800 RDRAM	PC800 vs PC2100
Sum - Double	1002.8	1415.0 (+41.1%)	1639.9 (+63.5%)	+15.9%
Sum - Int	772.5	796.2 (+3.07%)	1401.7 (+81.4%)	+76.1%
Sum - Short	689.3	760.5 (+10.33%)	1293.3 (+87.6%)	+70.1%
Sum - Char	521.5	601.0 (+15.24%)	1027.7 (+97.1%)	+71.0%