Thursday, June 13, 2002

Introduction

Recently, the world of DRAM was shaken-up just a bit by the arrival of the DDR333 memory standard. Despite the promise of higher performance, and greater bandwidth, however, our laboratory tests have so far detected little real-world benefit versus preceding generations of the DDR-SDRAM family. This, in no small part, came partly as a result of the particular module that we were employing -- which was rated with a latency of 2.5 - 3 - 3, with a command rate of 2T -- and partly due to the fact that we always tested it on AMD systems.

Since then, we've contacted numerous memory manufacturers for new samples, and Corsair has been kind enough to respond by sending us a module of their newest XMS3000 DDR333 RAM.

The XMS3000 certainly ranks as a high-performance device. It is rated for CAS latency of 2 - 2 - 2 with a command-rate of 1T at 166Mhz (DDR333Mhz), or CAS 2 - 3 - 3 with a command-rate of 1T from 166Mhz up to 185Mhz (DDR370Mhz).

To determine just how fast the DDR333 XMS3000 is, we'll be pitting it against a stick of DDR266 memory that is also rated for CAS 2 - 2 - 2 and a command-rate of 1T at 133Mhz (DDR266).

Since this article will essentially consist of a performance comparison between the Corsair XMS3000 DDR333 and our DDR266 module, we'll be employing the following benchmarks: Sisoft Sandra 2002, 3Dmark2001 SE, Business Winstone 2001 and PCmark 2002.

Of course, since the AMD Athlon itself has a maximum data rate of about 2.1GB/sec, all tests would be for naught if we tested the XMS3000 solely on an AMD platform. So, to make things a bit more interesting, we'll be testing on an Intel Pentium 4 system with a data rate of 4.2Gb/sec (133MHz FSB quad-pumped, 533Mhz effective) processor.

We also have to mention that DDR333 support has only recently made its way into Intel chipsets. Up until recently, consumers could choose between the i845 chipset -- which only supported DDR266 -- and the i850, which only supported Direct RDRAM. Since then, we've seen the introduction of the i845E, and the i845G and, even though neither officially supports the DDR333 standards, various manufacturers have tweaked their motherboards to make such combinations possible. As a result, the 2.7GB/sec of bandwidth of the XMS3000 should go to good use on such systems.

In fact, the Pentium 4 should be able to actually saturate the memory-bus between itself and the DDR333 XMS3000; something that we haven't seen happen yet on the AMD side.

Next: Test setup.