Introduction

RAM prices have fallen!

Earlier this summer we finally saw SDRAM prices drop to a reasonable level -- just in time for the launch of double-data rate (DDR) chipsets sometime in the next 40 days.

We realize that many of you (us included) will likely upgrade to a DDR motherboard and memory as soon as it's readily available, but in the meantime, the majority of consumers will stick with conventional SDRAM for the foreseeable future. (After all, the early adopters are always the guinea pigs used to sort out the bugs and glitches in today's newest products.)

With this in mind, we figured we'd delve into the topic of memory performance for those of you looking to upgrade. There are a lot of memory types and configurations out there. With the help of our memory provider Mushkin, we'll try and sort out some of the differences between the solutions currently available on the market, so you can determine which memory module is best for you.

PC100 vs. PC133

With VIA's adoption of the PC133 platform last year, an affordable, backward-compatible upgrade path from conventional 100MHz SDRAM was made available to consumers, increasing system memory bandwidth from 800MB/sec to 1.0GB/sec. How much performance does this equate to in real-world applications? The answer varies depending on the clock speed of your processor (as you'll find out once we get to the numbers), as well as the CAS latency of your memory module.

What is the CAS latency?

If you've shopped around for memory on Mushkin's website (or any other online retailer for that matter), chances are you've seen the term "CAS Latency" tossed around quite frequently. What does this term refer to?

To put it simply, CAS latency is the amount of time (measured in clock cycles) it takes for your memory to process a command. Two options are currently available, CAS latency 2 modules (CAS 2), and CAS latency 3 (CAS 3).

Essentially, it takes CAS 2 modules one less clock cycle to output data from memory than a CAS 3 module, making CAS 2 faster than its less expensive counterpart. Just like PC133 memory, the performance difference between CAS 2 and CAS 3 memory scales higher as the clock speed of the CPU increases.

How does this apply to memory modules?

CAS 2 modules currently come in two flavors, those designed to operate at 100MHz (PC100 CAS 2 for example) and those that are rated for 133MHz. Although PC100 CAS 2 memory is only rated for 100MHz operation, in many cases the memory can be successfully overclocked to 133MHz CAS 3.