Ratios

The Problem

There’s some mutterings out there that the new Intel boards have some sort of 275MHz “wall” that blocks people.

Yeah, there’s a wall alright. In many cases, it will be a self-constructed one.

To overclock the 200MHz FSB PIVs to any significant degree, you must run the FSB higher than the memory speed. The Canterwoods and Springdales give you
two options to do that, a 5:4 and a 3:2 FSB:Memory ratio.

What is happening is that people are going with the 5:4 ratio and setting aggressive memory timings. If you are running at a 275MHz FSB, that means the memory is running at 220MHz.

This is quite a bit to ask from any pair of memory sticks running at aggressive timings. (Actually, I’m pretty impressed these sticks are doing that well in tandem). There’s no memory out there now that can go much faster than that.

This causes a problem because if you have a 2.4C, 275MHz only gets you 3.2GHz, and at least some of these chips look capable of more than that.

The Solution

What many people need to do to get past 275MHz is to pull back on the memory settings. Slow them down a bit.

The way they should troubleshoot this is first test to see how far their CPU can go. The best and easiest way to do that is to run the system at a 3:2 ratio. This gets the memory out of the way as a potential bottleneck and tells you what the CPU/chipset can do.

It’s quite possible some will find that 275MHz is all the CPU/chipset can do, but then you’ll know not to blame the RAM.

It is certainly not going to hurt to provide extra cooling to the northbridge in these systems under any circumstances, either.

More likely, you’ll find that you can push the FSB up a bit more. Should that be the case, it’s time to relax the memory timings. Just keep saying to yourself “Memory settings aren’t everything,” and try slower settings.

Then do a before and after and see which works better for you.

Multiple Suspects

When you’re shooting for 3.5GHz or better with a 2.4C, a dual DDR board, and high-end memory, all three are potential bottlenecks, but typically, the underlying system will max out before the CPU.

Those of you who would prefer things not quite so dicey may wish to consider buying a 2.6C instead. However, it’s likely that with a 2.6C, the CPU will max out a little before the rest of the system.

Mind you, we’re not talking huge differences here.

Ed