Which DDR RAM module to buy for my motherboard? (latency vs. speed)

By mikeyd ยท 17 replies
Oct 1, 2009
  1. Hi there, I'm going to upgrade my memory, had a question:

    My Motherboard: Compaq 07E8h

    Here are 2 memory modules, I am about to buy one of them but which one should I choose ?....(I have already verified that both are compatible, but I have a different question)

    1GB DDR-333 (PC-2700) DIMM Memory Module
    LATENCY: 2.5-3-3-7


    1GB DDR-400 (PC-3200) DIMM Memory Module
    LATENCY: 3-3-3-8

    ^now the 1st one has a slower clock speed and slower transfer rate (I believe), but the 1st one also has better latency (timing) then the 2nd by a little bit.

    Should I just go with the "DDR-333 PC-2700" instead of the "DDR-400 PC-3200" since it has lower latency ?

    Or is their a chance I could overclock the faster one and achieve better or performance ?

    Motherboard: Compaq 07E8h

    Will this motherboard limit the clock speed and transfer rate, thus making it a better decision to go with lower latency memory ?

    thanks for any advice I will really appreciate it !
  2. mikeyd

    mikeyd TS Rookie Topic Starter

    I need 5 posts to be able to post a link, sorry.
  3. mikeyd

    mikeyd TS Rookie Topic Starter

    need 5 posts to be able to post links, sorry.
  4. mikeyd

    mikeyd TS Rookie Topic Starter

    need 5 posts before posting links, sorry.
  5. mikeyd

    mikeyd TS Rookie Topic Starter

    I need 5 posts before i can post links, sorry.
  6. captaincranky

    captaincranky TechSpot Addict Posts: 13,037   +2,558

    It's unlikely that your Compac board has any provision for overclocking whatsoever. My best advice is download a system information tool, and match the new memory as closely as possible with the memory already installed. You can use this tool "SIW" (system information for Windows); http://www.gtopala.com/ Download the "standalone English version" to your desktop, and double click it to run, No installation is required.

    Once upon a time, Compacs required "branded memory", and wouldn't work with just any old RAM.

    You should read the section in your mobo manual relating to RAM thoroughly before you attempt this project.

    Please read this guide also; https://www.techspot.com/vb/topic65114.html
  7. mikeyd

    mikeyd TS Rookie Topic Starter

    well thanks to the guy above, althought that info was inaccurate this compaq mb is compatible with almost any type of ddr ram it turns out.

    I inserted the ram and off i go and it's faster nd doesnt run out but it does say only under system info "available physical memory: 1.49 GB" so i don't know maybe the mb only recognizes 1.5 gb?

    and i still don't know if i would have any added benefit if i install the new 3.06 533ghz p4 processor b/c nobody seems to be able to answer the question as to whether the ram will work at the faster speed i got the pc2700 ram ddr 333 but i think the motherboard only supports slower then that does the cpu have anytyhing to do with it ?

    c'mon people wtf
  8. captaincranky

    captaincranky TechSpot Addict Posts: 13,037   +2,558

    The faster RAM runs the longer its latency becomes. So, it's quite normal that DDR 400 would have "looser" timings than DDR 333.

    DDR RAM is gradually disappearing and it's usually accepted that DDR 400 and DDR 333 are a direct interchange. The board and CPU control the speed of the RAM, and the RAM in any computer will always run at the speed of the slowest DIMM.

    Also, I don't think DDR 400 will run @ 400Mhz if the FSB of the board is 533Mhz or less.

    I think that Intel had more than 1 P-4 designated as 3.06Ghz, so you might want to check that. So here you need to check with Compac, to find out if your machine was ever shipped with that P-4 installed. If it was, then it will work. if it wasn't then it brings this project into the realm of "experimental".

    I am using a P-4 w/ DDR as my internet computer. However, I am in full knowledge that any Intel G31 chipset w/ a Pentium dual core (2xxx or 5xxx series) with DDR2 will run rings around it. A computer based on these parts can be built for less than $200.00 if your old drives, case, and PSU were used, and probably about $300.00 with all new parts. Not to mention, you can collect parts via Newegg's Email sales, mostly with free shipping, as you go along. Something to think about anyway.

    Most of us agree that attempting to overclock P-4 based computers nowadays is not worth doing in a risk/reward scenario.

    Besides, it's very doubtful that the stock Compac BIOS would allow this anyway

    You links are now active. However, Microcenter's website really doesn't take kindly to directly linking to a particular item. All it does is return a "page not found" error. Not your fault obviously, but I suggest using Newegg, http://www.newegg.com/Index.aspx?Name=Home as a reference instead, since they stock so many items,you'll often find the same things at each site. Besides, the reviews and prices are (usually) better at Newegg anyway.
  9. raybay

    raybay TS Evangelist Posts: 7,241   +10

    One key technical aspect to consider: The computer will run at the speed of the slowest memory module installed. Value Ram runs more slowly than top level memory. Even the best memory at $129 a module will not be very fast in that Compaq computer.
    However, if you run Corsair or Buffalo or Kingston or other easily available DDR400 PC3200 memory, you will have a nice performing machine... but it will never be a good gamer because Compaq is a low end budget computer with a low end motherboard, poor power supply, and inadequate cooling.
    DDR memory is no longer manufactured, so the price is going up every week.
    A computer using DDR2 or DDR3 will offer memory at substantially lower cost.
    Were it mine, I would begin assembling a computer with a terrific power supply and motherboard, then add to it as budget permits.
  10. mikeyd

    mikeyd TS Rookie Topic Starter


    also, apparently the northbride regulates the clock frequency of hte ram and is set to 266mhz, so apparently the ram won't run any faster then that even if i upgrade to the p4 3.06ghz with a bus speed of 533mhz (currently i have a P4 2.0ghz with bus speed of 400mhz) ?

    Idk i'm still confused

    also, am i still running dual channel memory mode with two 1 gb sticks of ram if the motherboard can only address 1.5 GB ?

    IF i want dual channel, should I go for TWO 512mb ram modules instead of TWO 1gb modules ?

    thanks my friends!
  11. mikeyd

    mikeyd TS Rookie Topic Starter

    so you think the ddr-400 pc-3200 ram will run faster on my particular machine then ddr-2700 pc-2700 ram ? (even though motherboard is 266mhz northbridge) ?

    i don't get it ...

    also, I can got the ram for $24 for each 1gb ddr-333 pc-2700 module, and I can get the ddr-400 pc-3200 module for the same price.
    a good price i thought

    yea i realize the newer systems are faster, but this thing is pretty damn fast already, i'm thinking with the new processor for 50 bucks it's all I need.

    thanks for any more info, still trying to figure eveyrthing out.
  12. captaincranky

    captaincranky TechSpot Addict Posts: 13,037   +2,558

    I think your computer may have onboard graphics, which would explain the "missing" memory.
    This would be accommodated so that with the video RAM set aside, the machine would still run in dual channel mode, yet only show the remainder as system RAM.

    Also,make sure that you don't confuse the "installed RAM, and "available RAM" numbers

    And no, that wasn't what raybay said, he was basically agreeing with me that it's time to save for a new machine.

    Check the prices @ Newegg

    This is only because you haven't used your current software on one of the new machines.
    As to the "I only need another CPU" issue, respectfully, I believe you're mistaken.
  13. mikeyd

    mikeyd TS Rookie Topic Starter

    thanks, actually hp JUST informed me that it was due to the onboard graphics, which I should have thought of, you're absolutely right.

    But they said it WILL NOT run in dual channel mode, although I've read on some of their support pages that it DOES INDEED run in dual channel mode with two of the exact type of memory modules, sooo....who knows...

    I still don't understand exactly what limits the ram speed, and if I was to get the faster cpu with faster bus speed would that allow me to utilize the faster ram at all ? or is it permanently limited by the motherboard, in what way ?
  14. captaincranky

    captaincranky TechSpot Addict Posts: 13,037   +2,558

    The motherboard limits the FSB speed, and the CPU must be matched to it.
  15. mikeyd

    mikeyd TS Rookie Topic Starter

  16. raybay

    raybay TS Evangelist Posts: 7,241   +10

    I seriously doubt that the comment on the Northbridge is true, based on the tests we have just run.

    System Bus and processor are two different things. CPU doesn't matter when it comes to memory speed, as it can always handle greater speed than that provided by the memory boards

    What matters are the memory sockets, and the Motherboard BIOS. An examination of the BIOS will tell you at what speed the memory will run... which, of course, is the same as the FSB...

    However, if you have different brands of memory modules, or different designations (such as Value Ram), The computer memory processing will run at the speed of the slowest memory module... regardless of what the motherboard would like to do.

    What is more, the memory works better, and faster, if all memory modules are identical... Gamer computers like to have memory from the same production run, and are sold in sets of two, four, six, or eight.
  17. captaincranky

    captaincranky TechSpot Addict Posts: 13,037   +2,558

    We can go on like this for quite some time, but at the end of the day, it's like I said up front; If the machine was ever shipped with the CPU you'd like to use, then chances are a BIOS update may be available to accommodate the faster CPU. If it isn't, then you probably won't be able to install it. Just because it's the same socket, has no bearing whatsoever on whether it will work or not.

    Prebuilt machines are not really intended for upgrading their core components, and are more or less intended to go from birth to grave in their shipped configuration.

    The only reason this machine seems fast to you, is because you don't own anything else. You're in an ideal situation to build another computer and use this one for internet. A second need not be outfitted with AV software, and without that, it will run maybe 4 times as fast as your Compac, on a $300.00 investment. Plus there's the added benefit of having a spare, and not having all of your business exposed to the net.

    We had a saying with respect to racing cars that went like this, "if it don't run, don't beat it". That seems to offer sound advice in this situation also.
  18. mikeyd

    mikeyd TS Rookie Topic Starter

    thank you captain cranky !

    you are right !

    However, despite installing a new hard drive which is much faster, 2 gb of ram, and taking out and reinstalling the processor after cleaning the heatsink and fan, i still have little confidence that I can correctly get the motherboard/psu installed correctly with all the little plugs for the fans and whatnot.

    I'm not going to attempt to build a computer until i have a friend or anyone that can help me with my initial build, i don't have a tremendous amount of patience with myself and I can see myself getting frustrated and accidentally breaking the mb or pcu.

    so, I would liek to install this other processor just because.

    I know that the new processor has a bus speed of 533 mhz, is this what I need to look up in the bios ?

    Or do I need to look up to see if the bios supports the actual speed of the processor which is 3.06ghz ??

    How do I get into the bios and look these up do you have a link perhaps ?

    thanks for any info or pointers or just tell me what I should look up on google, thanks again.

    I will eventually build my own system, but right now i don't have much time and I don't know anybody that can give me advice if I get stuck, and I know myself well enough to know that I won't have the patience to stop if I'm confused, I'll just end up breaking something and wasting money I don't have.
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