I have a Motherboard that supports 400/533 MHz RAM, and an Intel Dual Core 2x2.4 GHz CPU with FSB of 800 MHz. What memory should I use? 400 or 533? Is there any performance loss involved when 533 RAM downclocks to 400?
I'm not a memory master by any means, so I'm not sure if that would help your speed. I know the 800mHz FSB is usually related to the CPU's capabilities, but is also related to the whole system. I just don't know enough to help you with that question. Hopefully someone else can help you there.
Im running my 800mhz fsb p4 with 1:1 timming on my ram. I achive this though pc3200 or ddr @400mhz with timmings of 2.5-3-3-8.
D'oh! Saw the ddr2...
The ddr 533 will downclock to 400 mhz, you could probally get better timings too. Is it pc6400 or ddr2 with 400mhz effecive ( I dont think that exists) the ddr2 @ 400mhz is actully running at 800mhz wiile your 533 will run at 1066mhz. You should probally try to run your cpu and ram 1:1. Im not shure how to achive that with a pentium d but with a core 2 duo it would run ddr2 400mhz/800 effective with timmings of 4-4-4-12. If your using a core 2 duo, then get pc 6400 with the timings i just mentioned.
You should probally try to run your cpu and ram 1:1
He's got a HP oem board, those things are locked up pretty tight in the BIOS. If your cpu is running at 800mhz fsb, this means that it is 'quad-pumping' a 200mhz system bus (4x200). The ram, being Double Data Rate (DDR2), doubles this bus to run at 400mhz. Even if you have 533mhz ram, the system will still only use it at 400mhz unless you overclock the system bus. But I'm guessing that there are no adjustments in BIOS, right?
I would go for the 533 (or higher, there wasn't much difference in cost the last time I looked) ram so you can use it on your next, and hopefully clockable, system