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RAM only running at 400mhz instead of 800

By bobdole776 ยท 16 replies
Dec 31, 2008
  1. hi, i have an asus m2n-sli mobo and ocz 2 1-gig sticks of 800 mhz ram. now, cpu-z says that my ram is only running at 400 mhz i want it to run at 800. now i know that the ram needs to run at 2.1 volts but i cant go that high in the bios. could that be why its only running at 400mhz? if you cant tell me why, can you direct me to some software that can change the voltage or speed.thanks

    just found out that the memory is running at 1.8 volts

    just changed timings, now 4-4-3-12. a little faster, but still not running at 800 mhz.
  2. direwolf007

    direwolf007 TS Rookie Posts: 105

    I answered precisely the same question about a week ago on these forums, so I will give a short answer this time.

    DDR2 800 actually runs at 400Mhz and the "2" part means it transfers twice the data per clock, making it the equivalent of an 800Mhz DDR chip.

    Everything is perfectly fine and the timings are quite tight, too.
  3. MetalX

    MetalX TechSpot Chancellor Posts: 1,388

    Not quite true. DDR stands for Double Data Rate. Therefore, the data rate, or effective speed of the RAM is twice the actual clock speed. The "2" on the end just means that DDR2 is the second version or revision of the DDR technology, just as DDR3 is the third version. DDR3 does not run at three times the rated speed, it still runs at twice the rated speed, because it is Double Data Rate RAM.

    So when you see 400 MHz in CPU-Z, the RAM is running at 400 MHz, but data is transferring as though it were running at 800 MHz, therefore, it is listed as 800 MHZ RAM.
  4. direwolf007

    direwolf007 TS Rookie Posts: 105

    Which is pretty much what I said. I think what threw you off is the line:
    "means it transfers twice the data per clock"

    Which should have read:
    "means it transfers twice the data per clock over DDR1"

    The rest is perfectly correct.
  5. captaincranky

    captaincranky TechSpot Addict Posts: 12,534   +2,318

    Sorry, But the "2" Doesn't Mean That........

    NO, It isn't. The "2" in DDR2 has absolutely nothing to do with the "DDR" issue. In all cases, the memory clock runs at half the published speed. If we pursued your line of reasoning, then "DDR3" should transfer data @ three times per clock cycle, this simply isn't the case.

    "DDR" means "Dual Data Rate". The suffix number (1), (2), or (3) has no bearing on the fact that all three of these RAM types transfer data twice per clock cycle. Types 2 and 3 just do it faster. Types 2 and 3 are only "version" numbers.: http://en.wikipedia.org/wiki/DDR_SDRAM
    Hit Wikipedia, and see for yourself.

    When I am considering either bragging or complaining about having answered a question on multiple occasions, I have adapted the policy of examining whether I have answered the question completely correctly in the first place. This might be a good time for you to examine the worth of such a measure.
  6. direwolf007

    direwolf007 TS Rookie Posts: 105

    I stated, plainly, that DDR2 has twice the effective data rate of DDR1. This is correct and your argument is pointless. I was correct the first time around, and the last time I posted this as well.

    Follow your own advice, and take a good read of wikipedia for your own sake.

    Thank You.
  7. captaincranky

    captaincranky TechSpot Addict Posts: 12,534   +2,318

    By virtue of technological improvement only. You're still explaining it a bit incorrectly.

    And since I did read the Wiki page, and since my reading comprehension is well into collegiate levels, I really don't require your advice at any level, for any reason, or under any circumstance.
  8. adweston

    adweston Banned Posts: 242

    I got the same thing out this.. You say the "2" part means it transfers twice the data per clock.. .When in fact the "2" means that it's the second revision. DDR stops at 400MHz effective, DDR2 STARTS at 400MHz effective.

    The data rate of the motherboard is 400MHz. Because it's DDR, or double data rate, it runs at an effective memory clock of 800MHz.
  9. CCT

    CCT TS Evangelist Posts: 2,653   +6

    Just to 'muddy' the waters - my understanding is that, if the FSB runs 200 Mhz and you use DDR Ram, it thus runs at effective 400 Mhz BUT if it is ALSO made for and used in a Dual Channel configuration, it runs at effective 800 Mhz.

    Thanks for the time -

  10. bobdole776

    bobdole776 TS Rookie Topic Starter Posts: 19

    so, in all of this, even though its says its running at 400 mhz, its actually processing data at 800 mhz. i asked the question first because i heard stuff like if it is not completely compatible with the mobo, it will most likely run at 400mhz instead of 800, and like i stated in my first post, i can only get the voltage up to 1.95 when the memory is built to run at 2.10, and that is why i thought (and still kinda do) it was running at 400mhz instead of 800. if it is true that it is running at 400mhz, is there a way, if you cant do it in the bios, to change the voltage to 2.10? nvidia control panel has an option, but it is N/A. o, and one other thing, when i changed my timings, i did see a increase in access timing, but cpu-z still said it was running at 400mhz. and further more, dont bicker about who is right and who is wrong, just do your best to answer the question, thats all i ask.
  11. captaincranky

    captaincranky TechSpot Addict Posts: 12,534   +2,318

    If there wasn't enough voltage getting to the RAM, the machine might not "POST", (Power On Self Test), or you might get errors.

    Some high performance RAM will run at a lower speed a the lower voltage, then run at full rated speed a a higher voltage. DDR2 1066Mhz seem to be the place where this is most prevalent. Most of these DIMMs run at 800Mhz (effective) until the voltage is stepped up to > 2.1 volts.

    The timing of the RAM and the speed of the RAM are two entirely different attributes, don't confuse them.

    Nvidia settings might need software installed to function (.), (!), or (?) Pick the punctuation mark you feel most comfortable with.

    I doubt that Nvidia supplies the BIOS itself, and that's where you should be looking to adjust RAM voltage.

    I'm >> guessing<< that Nvidia has similar software to Gigabytes "Easy Tune", which allows you to adjust system performance from within Windows.

    The RAM is running at the correct speed. My suggestion is to run "Memtest86", and see if any errors occur. If not, leave the voltage setting alone.
    If errors do occur, then insufficient RAM voltage could be the cause.

    http://www.memtest.org/ Download memtest from here; http://www.memtest.org/ (ISO zip) use Nero or similar to burn to CD. This is an.iso "image" file and must be burned as such, don't try to copy and paste it to a CD.

    @CCT; That makes sense doesn't it, after all you have two separate pipelines of memory running simultaneously. But why the heck do they call it "PC6400"......?
  12. bobdole776

    bobdole776 TS Rookie Topic Starter Posts: 19

    thanks for the help
  13. CCT

    CCT TS Evangelist Posts: 2,653   +6

  14. captaincranky

    captaincranky TechSpot Addict Posts: 12,534   +2,318

    You're welcome, I hope we've help solve your problem.
  15. Tedster

    Tedster Techspot old timer..... Posts: 6,000   +15

  16. CCT

    CCT TS Evangelist Posts: 2,653   +6

    To further clarify (hopefully) this issue, the link I posted above



    "First of all, you should be aware that DDR2 memory is fundamentally similar to DDR SDRAM. Still, while DDR SDRAM can transfer data across the bus two times per clock, DDR2 SDRAM can perform four transfers per clock."

    There is a lot of use of the terms 'double pumped' and 'quad pumped' in relation to FSB frequencies and cpu/ram operation, and I am NOT at all sure they are always used correctly.

    In reality, FSB is FSB, it doesn't change. The way in which the FSB frequency is used changes, ie, the more 'paths' the more bandwidth, and thus greater performance.

    So, the way I see it, original SDRam operated at FSB frequency on a single channel, DDR doubled the channels for 2x the performance, and DDR2 doubled that again (but with some appreciable latency {slownesss} problems initially and with high heat still).

    With DDR3, you have essentially DDR2 redesigned to provide enhanced internal data transfer.

    A good article on DDR3 from the same source as my earlier link;

  17. bobdole776

    bobdole776 TS Rookie Topic Starter Posts: 19

    wow, that is the best translation i've heard so far, thanks for the post
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