Memory frequency in overclocking?

Question

I hope someone is willing to help me out as I am a complete beginner and very much out of my depth... having said that...
I'm looking to set up a very modest stable overclock... with next to no idea of what i'm doing.
I have an E4400 ms-7255 with 2 x 1gb RAM which runs at 333Mhz according to cpuz.
I haven't been able to find anything about 333Mhz RAM (if that IS indeed what i have - since i read it usually runs below its specs)
How does RAM frequency affect overclocking? Is it still possible/worthwhile or does the bandwidth limit it too much?
What settings would you recommend me attempting as a very safe attempt without having to flick the switch to reset my motherboard - and could you give me a bit of a run down/how to keeping in mind i'm less than leet.
Thanks so much
Samuel

Answer 1

Hello oscariouss,
the first basic thing you should try to get sorted before you get into overclocking is the difference between "real clock speeds" and "effective clock speeds" and also the inter-dependencies of different clocks and clock rates on an Intel System.
CPU-Z for example, shows you the "real" clock speed of your memory.  Now, as we are talking about DDR memory modules, the effective clock speed is always twice the real clock speed.  That is why "333 MHz" actually translates to DDR2-667 Mhz effectively. [DDR stands for "Double Data Rate" and this means that with each clock cycle, two transactions will take place (that is how you get the factor x2)]
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I haven't been able to find anything about 333Mhz RAM (if that IS indeed what i have - since i read it usually runs below its specs)
You probably have DDR2-667 memory modules.  To be absolutely sure about that, open your computer case and have a look at the memory modules themselves.  The brand and model name is usually mentioned on some sort of sticker.
CPU-Z should also display information about the brand and model name of your memory modules.  Have a look at the "SPD" Tab and see what it says in the top half.  You can also make screenshot and post them here for comparison.
To overclock the system, the most basic operation is to simply raise the FSB Clock Speed in BIOS.  For your current processor, the default FSB clock speed should be 200 MHz.  CPU Frequency is always the product of FSB Clock Speed x Multiplier and that is why raising the FSB Frequency will automatically result in a higher CPU Frequency.
Keep in mind, that memory frequency is also tied to FSB Frequency.  The relation between FSB Clock and memory clock is regulated via FSB/Memory Ratios that can be set in BIOS.  If your FSB Clock speed is 200 MHz and memory clock speed (real) is 333 MHz, that means that FSB/Memory Ratio is set to 1:1.66 in BIOS (probably via an AUTO setting).
Now, if you raise FSB Clock Speed, memory clock speed will rise as well.  If you would increase FSB Frequency to 210 MHz in BIOS and the FSB/Memory Ratio remains @1:1.66, memory clock speed will be forced to:
210 MHz x 1.66 = 348,6 MHz [or DDR2-697 MHz effectively]
Please also remember, that your board is a budget model whose VIA Chipset is not really a high-end/high-performance piece of hardware.  Overclocking is not exactly what the designers had in mind here.  That means that the overclocking potential will most likely be limited and the BIOS will probably lack specific OC relevant options that will help to  reach higher clock speeds.  That, of course, does not mean that you should not at least try to check what is possible, but you should not be disappointed when you find out that you are unable to stabilize the system above certain frequencies.
I don't know which options you have to influence memory clock speed (or more precisely FSB/Memory Ratio) in BIOS.  Just have a look what options you have there and tell us here.