Because Rambus technology is able to transfer data on both the rising and falling clock edge, the effective performance is doubled the memory speed, when compared to SDRAM. For example, PC800 RIMMs are really running at 400MHz, but because it can transfer twice as much data in one cycle, it's labelled PC800 instead of PC400. For marketing purposes, most people will refer to RIMM as PC600 or PC800, instead of using the true memory clock speed.

So it's great that we now have a memory technology that's eight times as fast as SDRAM, and can possibly scale higher in the future. So why is SDRAM still around? The answer is, the current cost of Rambus memory is almost five to six times the cost of SDRAM! For example, the current average cost of a 128MB PC100 DIMM is about $150. The cost of a 128MB PC800 RIMM is approximately $900! Is the performance of Rambus memory that much better than SDRAM? Let's take a look...

Here's the quick rundown of the components used in testing:

System Board	PREMIO 820R for Rambus PREMIO 820S for SDRAM
Chipset	Intel 820 AGPset
BIOS	PREMIO 820R - Phoenix version P03 PREMIO 820S - AMI version 1.1B7
Processors	Intel Pentium III/733MHz
Memory	128MB PC800 (two Samsung 64MB PC800 ECC RIMM) 128MB PC700 (one Kingston 128MB PC700 ECC RIMM) 128MB PC100 (one Samsung 128MB PC100 DIMM)
Hard Drive	Western Digital 27GB 7,200RPM ATA66 (WD273BA)
DVD-ROM	Creative Labs 6X DVD
Video Card	Diamond Viper 770 Ultra AGP (32MB)
Operating Systems	Windows 98 Second Edition Windows 2000 Professional build 2195 Windows NT 4.0 Workstation with SP5

Ziff-Davis Winstone 99 measures overall system performance by running through a series of commonly used business and engineering applications. Higher number means better performance. Winbench 99 measures the performance of a specific part of the system; such as CPU performance. For both test suites, higher numbers mean better performance. Content Creation 2000 is focused on applications used to create Internet content. For example, Adobe Photoshop, Adobe Premier, Macromedia Director, etc.

The green bar represents PC100 SDRAM, while the orange and cyan colored bars represent Rambus PC700 and PC800, respectively.

The chart above measures a system's overall performance under Windows 98SE. The differences between the three does not appear to be too significant. But a single point difference in Winstone 99 Business under 98SE does matter. Also, keep in mind that Winstone 99 BUsiness only measures commonly used business programs like Microsoft Word, Excel, PowerPoint, etc. These applications typically do not stress out the CPU and/or memory subsystem. And notice that the performance level for the Rambus PC700 and PC800 is very close to each other.

The chart above measures a system's overall performance under Windows 2000. This time, we're using the Winstone 99 Highend test suite, which runs applications such as CAD, CAM, engineering, C++ compilers, etc. In other words, applications that will stress out the entire system. Here we see the advantage of Rambus over SDRAM; clearly, Rambus's performance is better. But is it eight times as fast as SDRAM? Probably not...

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