I hope someone can help me with this. I previously had 1GB of DDR2 RAM (512 x 2 modules). I just upgraded to 4GB of DDR2 PC2-5300, which is the same type and speed as the old RAM.

The stickers on the new modules state DDR2-667MHz. I checked with CPU-Z and the memory claims to be running at a frequency of 333.3MHz. Why is it only running at half the possible speed? My FSB is 800MHz, and CPU-Z reports a FSB:DRAM ration of 6:10. Some of this is alien to me, but I heard that 1:1 is the ideal ratio. CPU-Z reports a bus speed of 200MHz, x 4 to a rated FSB of 800MHz, a core speed of 3000MHz and a multiplier of 15.

I went into my BIOS and tried to set the RAM frequency to 667. It accepted the change, but CPU-Z still reports 333MHz.

Can someone explain? And if possible, tell me how to get the frequency up to 667MHz? Thanks.

I think if you install RAMs with difrent frequencies then everything will act using the lowwest frequency

EADM

Then I should have been clearer. I took out the old modules and inserted 4 brand new modules of the exact same brand, type, and frequency. All four modules are 1GB DDR2 PC2-5300 667MHz.

Thanks.

Your RAM uses DDR (double data rate) technology. DDR667 RAM actually runs at 333MHz, not 667MHz, but the speed is "effectively" doubled.

And your 800MHz FSB CPU actually runs at 200MHz. Unless things have changed, best performance on a P4 system is when the CPU:DRAM ratio is 1:1. That means your RAM should run at 200MHz (aka PC2-3200/DDR400) regardless of the fact that it's rated for 333MHz/DDR667.

At least if you decide to overclock, you shouldn't have to worry about your RAM holding you back...lol

So then what is the point of the 800MHz FSB if it only works at 200MHz? Some people have told me it functions at the full 800MHz, meaning the RAM's full 667MHz is being used.

I also heard that 333MHz with DDR2 RAM is equal to 667MHz. But I am hearing a lot of things.

"So then what is the point of the 800MHz FSB if it only works at 200MHz?"

The 800MHz label is a misnomer. The actual speed is only 200MHz, but since Intel "quad pumps" the FSB, 4 bits of data are carried per clock cycle, so the effective bus speed is 800MHz. It's really more in reference to data transfer rates (aka bandwidth) than it is to clock speed.

See response #3

http://www.computing.net/hardware/wwwboard/forum/33706.html

Jam, I read your response in that other thread and you sound like a smart guy. It makes a little more sense now.

So am I to understand that my RAM is actually being used to its maximum potential? In other words, my RAM is in fact NOT being limited by the CPU? Meaning that I don't really have a problem and I need to stop worrying.

Ideally, a CPU:DRAM ratio at 1:1 will provide optimal performance. With your CPU running at 200MHz & your RAM at 333MHz, your ratio is closer to 3:5. If anything, your RAM is being held back from reaching it's full potential by your CPU.