What does "DDR3 1066 (PC3 8500)" mean ?

Hey guys, I don't really know much about RAM, except that there's 3 types right now(DDR,DDR2,DDR3)
I was wondering what the numbers on this page under "Speed" meant ?

DDR3 1066 (PC3 8500)

Specifically the "1066" and the "PC3 8500"
19 answers Last reply Best Answer
More about what ddr3 1066 8500
  1. 1066 and PC3 8500 are the same number in fact, just different standards. One is the actual described speed and PC3 xxxx is the module name

    1066 represents a speed of 1066MHz.
  2. Best answer
    DDR = Double Data Rate
    3 = Version of DDR
    1066 = Rated Frequency
    PC3 = {acronym same as DDR3} theoretical bandwidth
    8500 = frequency JEDEC 8500/8 = 1063 theoretical bandwidth
  3. I see, I see.
    Thank you guys for replying.

    Why is the DDR3 1333 listed 3 times ?
    DDR3 1333 (PC3 10600)
    DDR3 1333 (PC3 10660)
    DDR3 1333 (PC3 10666)
  4. They are all JEDEC varients; SPD with 'Rated' of 1333 MHz.
  5. Alright, I think I get you.

    One more question.

    Say I was picking out a motherboard, and it called for DDR3 1333 RAM,
    what would be the difference in performance out of those 3 JEDEC varients ?
  6. The performance is not the issue, the 'compatibility' IS the issue. Therefore, you with to look at either the MOBO Certified {QVL} or RAM Mfg's Tested RAM {Configuration}.

    Q - What MOBO?
    Q - What Budget?
    Q - What OS? {including 32-bit or 64-bit}
    Q - How much RAM do you need?

    32-bit caps you at 4GB period so 2X2GB, 4GB is recommended for 64-bit, 4GB 'sticks' for Rendering {e.g. 2X4GB, 4X4GB or LGA 1366/2011: 3X4GB, 6X4GB}.
  7. Quote:
    The performance is not the issue, the 'compatibility' IS the issue. Therefore, you with to look at either the MOBO Certified {QVL} or RAM Mfg's Tested RAM {Configuration}.

    I don't know what either of those are ?

    Although, I can answer those questions:

    A - Pretend it's this one
    A - $700 or less
    A - Windows 7/64-bit
    A - 8gb of RAM
  8. I have told you many times that CPU-Z wrongly calculates DDR3 frequencies. PC3-8500 can't operate higher than 533MHz without overclocking. So, what are 609MHz and 685MHz? It's just an ordinary mistake of the software. Do not trust CPU-Z.
  9. PC3-8500/8 => is 1066 MHz; 1066/2 = 533 as reported with CPU-Z; ANY SPD/JEDEC reported on CPU-Z is 'HALF' it's operational Frequency. In other words CPU-Z reports "I/O bus clock" NOT "Data rate" ->

    I 'wish' CPU-Z 'did report' Data Rate it sure would calm people down!

    Trying to provide Certified/Tested RAM on a 'pretend' MOBO is pointless. However, the $700 Total Budget will really hamper your choices in RAM. I would use 'Value' RAM, 4GB {2X2GB} and get 1333 MHz DDR3 with either CAS 8 {8-8-8} if possible or CAS 9 {9-9-9}. Once you decide on a MOBO simply enter the information on the RAM Mfg's site 'Configurator' or use the MOBO's QVL list as listed on it's website.

    The ASUS P7P55D-E Pro is an excellent MOBO, but it's too much for a $700 build.

    Example - RAM ASUS P7P55D-E Pro:
    QVL {see Memory Support List} -
    Tested Corsair -
    $45 Example ->
    $99 Example ->

    Keep in mind the RAM speed and performance is a primary function of the Quality of the IC, Frequency & CAS only give you a 'ballpark' idea. Ideally, you want high frequency with low-tight CAS. Meaning there are plenty of 1333 MHz RAM that can outperform 'cheaper/IC' 1600 MHz RAM. Only benchmarking with several 'Testing' Apps will show true and/or potential performance.

    I would strongly recommend that you put together a Spread Sheet with Components & Costs before ordering anything. If you don't have Excel -> Free Open Office

    Great Building Guide {tecmo34}
  10. Sorry if i keep asking questions still, haha, i thought that one was gonna be the last.

    Right now I'm using this site to learn about how to build a gaming computer:
    And so everything's still up in the air, there aren't any finite parts I've decided on.

    Kinda going back to my prior question, out of those 3 DDR3 1333's, which would be compatible with the motherboard I picked out ?
    And how would I figure that out ?

    QVL {see Memory Support List} - [...] templete=2

    The memory support list page won't load for me.
  11. Again, use my friend's guide -> and also here's his Building Guide ->

    From my Example above, they are ALL compatible Sets for the ASUS P7P55D-E Pro - I used the "Tested Corsair" and cross-referenced them from Newegg. My links all work but your copy/pasted doesn't {cut the middle of links out}. If you choose a different MOBO then go to and use the Find Compatible Products ->
  12. No i mean out of these 3:
    DDR3 1333 (PC3 10600)
    DDR3 1333 (PC3 10660)
    DDR3 1333 (PC3 10666)


    What if I want to use something other than Corsair ?
  13. DDR3 1333 (PC3 10600)
    DDR3 1333 (PC3 10660)
    DDR3 1333 (PC3 10666)

    Means nothing about 'performance' it means revisions of JEDEC and (PC3 10666) is the latest standard for 1333 MHz DDR3. Again, 2 different sticks of 10666 will perform diffidently; {unseen IC's}, CAS Timings, Cooling, etc. The IC or performance is somewhat tied to the prices but the 'true measure' is to Google Benchmarks +RAM Model Number. Further, at some point the higher costs don't make sense in most builds whereas the 'extra' savings should be used for improved: CPU, GPU, SSD, etc.

    For other RAM simply go to the RAM Mfg's site and select your MOBO from their configuration online tools:
    G.SKILL ->
    Kingston ->
  14. Alright thanks man,

    Are all 3 of those DDR3 1333 JEDEC revisions compatible with the ASUS P7P55D-E Pro ?

    Is the only way to find out by going to the RAM mfg's site ?
  15. You'd have to research backwards to find out what RAM is of what JEDEC type and/or QVL or Tested. My best guess is that 10600 and 10666 is on the list, there are fewer 10660 but I assume if you researched them all chances are there's some of each...

    Again, use either method I recommended {QVL or Tested}, Matched Sets and if adding 4 sticks Duplicate Matched or 'Quad' Sets.
  16. Quote:
    Matched Sets and if adding 4 sticks Duplicate Matched or 'Quad' Sets.

    just to be clear,
    you mean match the RAM sticks,
    and if i want 4 sticks cuz there's 4 slots,
    duplicate the 2 sticks to make 4,
    am i right ?
  17. Yes, buy in sets of 2 or 4 'sticks'.
  18. Alright thank you good sir for answering all my questions,

    that will be all, haha.

    And thanks for those 2 guides.
  19. Best answer selected by ostrich2.
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