Confused about RAM voltages. Help!


You probably get this problem a lot, but I do not want to risk a failed startup when I build my first computer sometime in July. I have almost my entire rig set out, but I cannot seem to figure out this memory voltage thing. All of the motherboards I have went through specified something about 1.8V RAM, and RAM with very low speeds seem to be the ones with a 1.8V rating. I would like to get some DDR2 1066 or higher, but it seems they all exceed 1.8V. Most of them are 2.0-2.2V.

So, my question is. The slots even if they say rated for 1.8V or whatever, can they be used with modules of higher voltages?

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  1. Yes, but you will have to go into the bios setup and change the speed, timings, and voltage to match the spec's on the ram that you are going to install. Get some good DDR2-800 with 4-4-4-12 timings. You will have less problems.
  2. Ok. This is not exactly 4-4-4-12, but its close:
  3. JEDEC is the governing body that certifies official memory ratings, their voltage for DDR2 is 1.8v and DDR3 is 1.5v. Originally they only certified DDR2 speeds of 400, 533, 667 and 800 but since have added 1066 but all of them are still 1.8v. Since DDR2 first came out technology has improved to allow for higher voltages and lower timings. Companies seek out these chips and market them as EPP (Enhanced Performance Profiles). If you download and run CPUZ and select the SPD tab it will show all the speeds that your RAM is rated for. Motherboards default the the JEDEC standard 1.8v so any RAM sold at different voltages and timings requires the user to manually change the settings in the BIOS. The settings you see (for your RAM 5-4-4-15 2.1v) are settings the manufacturer guarantees the memory will overclock to.

    All that being said the memory you bought isn't bad but it's not the best. There is very little difference and no noticeable difference between DDR2 800 and 1066 so I think you'll be fine with what you have.

    If you look at these they have very similar timings to the memory you linked. The sticks I linked work at the JEDEC standard 1.8v which means they are using better chips because they don't need the increased voltage in order to reach those timings.

    This is a shot from the memory in my system so you can see what I'm talking about. It was sold as DDR2 1066 5-5-5-15 2.05v. If you look under max bandwidth you see it being identified as DDR2 800 because it actually is and the 1066 is an overclocked rating.
  4. Thanks alot!
  5. Did that answer all your questions?
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