Wednesday, August 25, 2004
How Much Does RAM Latency Impact Performance?
Posted by Jason Dunn in "ARTICLE" @ 05:00 AM
The above question is something I've always wondered about - how much does RAM latency really matter? Historically I've always opted for fast RAM, but on the most recent RAM purchase, prices were quite high and I opted for some slower CAS 3.0 RAM. The result? I didn't notice any difference, nor was I expecting to. This is a great article for you hardcore hardware tweakers out there, and the bottom line is this:
"Our tests show that improving RAM latency only makes a small difference in the performance of modern high-end PCs. The amount of improvement varies greatly depending on the application you're running, but it's safe to generally characterize the improvement by saying that, compared with CAS 3.0 RAM, CAS 2.5 will give you a 1% to 2% speed boost, and CAS 2.0 will give you 2% to 4%. Those are definitely small numbers, to be sure. System manufacturers often fight with their competitors over performance variances that small, though, so it shouldn't be viewed as insignificant. In fact, it's not uncommon for a new high-end CPU to be released that's just a couple hundred MHz faster than the previous best, giving you a performance advantage of 5% or less."
It goes on to say, however, that in high-end PCs and certain applications, faster RAM can make a significant difference. How often you'll be using those applications, of course, is what will make the investment in CAS 2.0 RAM worth it or not.
"Our tests show that improving RAM latency only makes a small difference in the performance of modern high-end PCs. The amount of improvement varies greatly depending on the application you're running, but it's safe to generally characterize the improvement by saying that, compared with CAS 3.0 RAM, CAS 2.5 will give you a 1% to 2% speed boost, and CAS 2.0 will give you 2% to 4%. Those are definitely small numbers, to be sure. System manufacturers often fight with their competitors over performance variances that small, though, so it shouldn't be viewed as insignificant. In fact, it's not uncommon for a new high-end CPU to be released that's just a couple hundred MHz faster than the previous best, giving you a performance advantage of 5% or less."
It goes on to say, however, that in high-end PCs and certain applications, faster RAM can make a significant difference. How often you'll be using those applications, of course, is what will make the investment in CAS 2.0 RAM worth it or not.
