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DDR800 ram in a 667 mobo dilemma

By thebluemeaner ยท 16 replies
Jun 11, 2008
  1. I currently own a e2160 but im planning on upgrading to a e8400 processor soon, these are my current specs (except for the vid card which im still waiting for to be delivered)

    e2160 @ 2.9ghz
    320GB Samsung Drive
    Biostar 945GC Micro 775
    2 gigs of generic RAM 667 (Cybertech brand) (timings 4-4-4-12) running 1:1 with cpu
    XFX 8800gt Zalman edition

    My motherboard allows changes in FSB (it has to be a 1066 cpu other wise it chokes easily) but no changes in voltages so I'm limited to what I can reach on stock voltages.

    The motherboard accepts 667 ram, but ive overclocked it and it can easily reach 800 mhz 24/7. Also the motherboard allows to change ram timings and voltage up to 2.2 volts.

    The questiong is the following.

    Since I'm trying to overclock the E8400 to at least 3.6 ghz (fsb of 400) would I benefit from using ddr800 sticks on my pc? if I run a 1:1 separator the ram would be running within its specs. Can I do that? Will I achieve a better overclock if I do? thanks for the replies.
  2. Gazeppi

    Gazeppi TS Rookie

    As far as I know a mobo that is rated for 667 cannot hold 800 even if it is overclocked.
  3. Gazeppi

    Gazeppi TS Rookie

    I stand corrected. It will work but only run at 667mhz
  4. thebluemeaner

    thebluemeaner TS Rookie Topic Starter Posts: 64

    I know, if I overclock the 800 ram that is running at 667 I should get it running at its rated speed right?
  5. Gazeppi

    Gazeppi TS Rookie

    I don't know if you'll get it to 800, but can get it higher than 667
  6. nickc

    nickc TechSpot Paladin Posts: 923   +11

    u should be able to set the mem. at 1:1 and get it to run at the speed needed with the processor as needed.
  7. fullmetalvegan

    fullmetalvegan TS Enthusiast Posts: 123

    I was curious about this also. If I have a stick of DDR2 1200MHz on a 1200MHz certified DDR2 board... does that mean I will be unable to overclock it to 1333MHz to match my CPU FSB? Because I know with my current DDR3 system I can overclock the 1333MHz RAM to 1600MHz, maybe because it has memory support that high. But I am unclear how that will apply to DDR2 motherboards that don't stock support it beyond 1066/1200MHz.

    Basically, if I stick in DDR2 and overclock it to 1600MHz say, will they actually work at that speed? It seems related to how a motherboard says it supports 1333MHz FSB and a 1600MHz (OC) FSB. As if to imply, these devices will reach such speeds overclocked and simply state what is natively supported in the specifications.
  8. raybay

    raybay TS Evangelist Posts: 7,241   +10

    You will have errors if you try to drive a 667 to higher speeds for very long.

    Don't understand why you are doing this, when it is easier and less costly to use the right board and the correct memory for it.
  9. fullmetalvegan

    fullmetalvegan TS Enthusiast Posts: 123

    Yeah... making a 667MHz or 800MHz sticks of ram to 1:1 with your CPU will kill it in no time, that's a huge overclock.

    I want to know if that's even possible too, will it actually run my 1200MHz sticks at 1600MHz overclocked if the board only says it has a 1200MHz native support. Because there is no DDR2 stick that natively has 1333MHz speed.
  10. thebluemeaner

    thebluemeaner TS Rookie Topic Starter Posts: 64

    The reason I'm asking this is because I'm planning to upgrade to a wolfdale soon. E8400 to be exact. The fsb of this processor is 1333, so it would run at 1:1 exactly with my 667 ram, leaving me with not much overhead to overclock. That is why I wondered if I could use some 800 ram and set it to run at 667. Then by keeping the ratio 1:1 I could run a 1600 fsb without straining the memory. It is still unclear to me if it is possible since some of the answers are vague, but I assume it might not be a good idea to try that. Upgrading motherboards isnt easy in the country I live in since modern motherboards are scarce and expensive.

    By the way by saying 1:1 I mean pairing the fsb of the processor divided by 4 (1333/4) and the fsb of the ram divided by two (667/2)
    I believe its known as "separator". I dont see how pairing 800 mhz ram (800/2) with a 1600 fsb cpu (1600/4) is a huge overclock. Its only 133 mhz apart from 667 and 1333
  11. nickc

    nickc TechSpot Paladin Posts: 923   +11

    if u get a good board it will run the E8400 at 1600 and u can run the mem. at the 800MHz and not down clock it at the 1:1 ratio.and yes it is not a problem to run the 800 mem. at 667.
  12. raybay

    raybay TS Evangelist Posts: 7,241   +10

    You can use the 800 ram at 667. You do not need to re-set it. It will work at any FSB slower, but not faster.
  13. fullmetalvegan

    fullmetalvegan TS Enthusiast Posts: 123

    Yeah I was thinking differently, I overlock my memory to 1600MHz to match my CPU overlocked at 1600MHz - so they share a literal 1:1 ratio on the MHz frequency. I was just assuming you meant that. =]
  14. thebluemeaner

    thebluemeaner TS Rookie Topic Starter Posts: 64

    Thanks everyone for their contributions, I finally decided to buy the new ram and give it a go, and it worked, I bought some pc 6400 crucial ballistix ram and I've got it to work at 800 stable on my motherboard so apparently if you have no other choice in ram at your motherboards rated speed you can still buy some faster ram use it...
  15. raybay

    raybay TS Evangelist Posts: 7,241   +10

    If you check your processes, you will find that it is running at a slower speed than that for which it was designed... but that is ok. Memory runs at the speed of the cpu and the motherboard Front Side Bus. It is impossible for it to run faster.
  16. nickc

    nickc TechSpot Paladin Posts: 923   +11

    raybay, I am running Crucial Balistic DDR2 1000 and have it set at (SMM) 2.4 ratio, are u telling me the the mobo. is lying to me and it is not running that fast?
  17. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,443   +36

    As far as I've seen, that's not true. AFAIK, using the appropriate divider settings, it is possible to set the FSB:RAM frequency ratio to whatever you want, assuming the motherboard's chipset supports this feature. If you have seen anything to the contrary though, please do let me know.

    Ultimately however, the FSB:RAM ratio does not produce a large performance difference for two reasons:
    1. The large majority (~80%) of memory access operations are done via the cache.

    2. The CPU does not always want to communicate with the RAM when accessing features such as the onboard sound etc.

    So it's made out to be extremely important, which it isn't. Forget about it and concentrate more on getting the most out of your CPU, since a higher CPU frequency will get you much better real life performance than a 1:1 ratio with your FSB and RAM.
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