Question about overclocking and ram

[revanrules]

Hi, I'm a newbie when it comes to overclocking seeing as how I haven't done it, and I've got a few questions regarding overclocking and ram.

If I had an E6750 and some DDR2-800 ram and I wanted to overclock the cpu to 3.4GHz, then I would need to raise the FSB to 425MHz, because multiplying that by 8 gets you the 3.4GHz, correct? And if I wanted to keep a 1:1 ratio then I'd have to overclock the ram from 400MHz to 425MHz, right?

But what if I had DDR2-1066, then would I have to underclock the ram from 533MHz down to 425MHz? Because if I wanted a 1:1 ratio and I left the ram at stock speeds, then overclocking the cpu to 533MHz would give me 4.26GHz (which seems ridiculous), right? Is there any reason to get DDR2-1066 if I can't use it at it's stock speed and have to underclock it?

 

[SerpentRoyal]

High quality 1.8V DDR2 800 should be able to hit +450MHz at 2.0V with 5-5-5-15 timing.

 

[myocardia]

All memory, like all processors, will overclock to some extent. The more expensive memory overclocks higher, but even the cheapest PC6400 will have no problem doing 425 Mhz, including any of these.

 

[5t3v0]

You can use a memory multiplier so if you ran your components at stock speed you'd use a 3:4 cpu:memory ratio to run the cpu at 400 & the ram at 533. There's little performance gain from doing this so the extra cost of DDR2 1066 is not worth it. Another option if purchasing DDR2 1066, is to run it synchronously with the cpu and tighten the timings e.g. from 5-5-5-15 to 4-4-4-12. Again the performance benefits are minor so dont justify the expense. DDR2 1066 does become useful when overclocking low multiplier cpus using big MHz increases.

As myocardia says, most DDR2 800 will overclock to 425 & better quality ram will go even further by dropping the timings and/or increasing voltage. Sometimes you dont even have to relax the timings. My Corsair was moderately priced & does 450MHz on its rated specs of 4-4-4-12 at 2.1v. It might do more but I've never tried it.