Does RAM Latency Matter?

By Jason Cross  |  Posted 2004-08-19 Print this article Print

Deep Tech: Memory manufacturers continue to sell faster and faster RAM, often touting lower latency as a major selling point. Does this more expensive RAM actually improve system performance?

System memory is often the forgotten cousin among components when youre building a new PC. A lot of PC builders just buy whatevers out there, as long as it works in their systems. Some enthusiasts take the opposite route. They get expensive ultra-high-frequency or low-latency memory, hoping it will give them a big performance boost. Most major memory manufacturers now offer special low-latency memory. Kingston has a low-latency line of its HyperX DDR400 RAM. Crucial offers a high-performance line called Ballistix. OCZ Technologies has sold specialized low-latency RAM for a long time. And an "LL" designation shows up in Corsairs XMS memory line to indicate this characteristic.
You can pay from 30 percent to 100 percent more for these low-latency offerings, but are they worth the extra money? ExtremeTech examines the effects of low-latency memory on two high-end systems to determine its value to PC builders.
When you buy RAM, youll see two main speed ratings listed: frequency (the maximum rated clock rate) and latency. Memory speed is certainly important if youre considering overclocking, but for now were concerned only with latency. Low-latency memory, running at low-latency settings, supposedly speeds up your system without requiring you to overclock it. Memory latency is almost always designated in one of two ways. Its either a single number denoting the CAS latency, or a string of four numbers denoting several latencies. CL=2.5, CAS=2.5 or C=2.5 would be common "single number" listings for RAM with a CAS latency of 2.5 cycles, for instance. A four-number designation would be something like 3-4-4-8, in which the four numbers relate to CAS – tRCD – tRP – tRAS. To read the full article, click here.
Jason Cross Jason was a certified computer geek at an early age, playing with his family's Apple II when he was still barely able to write. It didn't take long for him to start playing with the hardware, adding in 80-column cards and additional RAM as his family moved up through Apple II+, IIe, IIgs, and eventually the Macintosh. He was sucked into Intel based side of the PC world by his friend's 8088 (at the time, the height of sophisticated technology), and this kicked off a never-ending string of PC purchases and upgrades.

Through college, where he bounced among several different majors before earning a degree in Asian Studies, Jason started to pull down freelance assignments writing about his favorite hobby—,video and computer games. It was shortly after graduation that he found himself, a thin-blooded Floridian, freezing his face off at Computer Games Magazine in Vermont, where he founded the hardware and technology section and built it up over five years before joining the ranks at ExtremeTech and moving out to beautiful northern California. When not scraping up his hands on the inside of a PC case, you can invariably find Jason knee-deep in a PC game, engrossed in the latest console title, or at the movie theater.


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