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Unsure of Ram Speed I can use??

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Unsure of Ram Speed I can use??

jason9922
I need to purchase 4 1 GB sticks of ram for a HP Pavilion PC Desktop Model #A1720N Product# RT641AA #ABA. The user guide says that the ram to update it with is PC2-4200 MB/sec 553 MHz 240 pin DDR2 SDRAM. What I am confused on is there is other PC2-6400 800 MHz ram for sale and it seems like as long as I bought and used two pairs so they are all the same exact stick of ram that the dual channel would work great and run even faster. I am unsure if it even matters to buy ram that has speeds a little faster but figured I'd see what you guys thought. Thanks!!
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    HAL 9000 Moderator

    Try reposting this in the 'Q&A' forum. The 'Discussion' forum is for matters of general discussion, not specific problems in search of a solution. The 'Water Cooler' is for non-technical discussions. You can submit a question to 'Q&A' here:

    http://www.techrepublic.com/forum/questions/post?tag=mantle_skin;content

    There are TR members who specifically seek out problems in need of a solution. Although there is some overlap between the forums, you'll find more of those members in 'Q&A' than in 'Discussions' or 'Water Cooler'.

    Be sure to use the voting buttons to provide your feedback. Voting a '+' does not necessarily mean that a given response contained the complete solution to your problem, but that it served to guide you toward it. This is intended to serve as an aid to those who may in the future have a problem similar to yours. If they have a ready source of reference available, perhaps won't need to repeat questions previously asked and answered. If a post did contain the solution to your problem, you can also close the question by marking the helpful post as "The Answer". .

    However in the mean time The RAM should work OK but it may not necessarily be any faster. It all depends on what the M'Board can use and the FSB of the CPU. If the M'Board can not use the faster RAM it's not going to improve performance and if the FSB of the CPU itself doesn't suit 800 MHZ RAM in Dual Chanel Configuration the System is going to run at what the CPU can support.

    So yes you should be able to used Matched Sets of RAM with the faster speed but it doesn't mean that the system is going to be any faster unless you increase the amount of RAM fitted. Even they it will just seem to perform faster but not actually run the internal commands any faster, you'll just be reaping the benefit of More RAM.

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    CharlieSpencer

    Both of these major RAM manufacturers have utilities on their web sites to help you. Download the apps and they will tell you what you have, how much you can add, and the exact part numbers you need.

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    NickNielsen Moderator

    Your processor and the memory control chips are what determine the speed of your memory buss . Installing faster RAM will not result in increased performance; the RAM will simply run at the lower speed.

    On the other hand, installing slower RAM will reduce performance, and can result in unreliable operation.

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    Deadly Ernest

    speed unless the FSB can handle a higher speed too.

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    NickNielsen Moderator

    "Installing faster RAM will not result in increased performance..."

    I might could have worded it better, though.

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    NickNielsen Moderator

    that the faster RAM is on sale for a lower price than the specified RAM.

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    Deadly Ernest

    being in other areas than FSB.

    Another to to watch out for is I once had a board where you HAD to match the RAM speed to the FSB or it didn't work right, never could work out why, but put in slower or faster RAM and it didn't all register - was real weird. I lived with that for a few years until I upgraded.

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    TheChas

    I may have stumbled upon this too late for my comment to be of value.

    Anyhow, check the specifications closely as faster RAM may actually run slower if you cannot match the required clock speed for the faster RAM.

    Why?
    Most of the time, faster RAM has a higher CAS latency number and can take more clock cycles to actually respond to data changes and queries.

    The CAS rating can also explain the issue that Deadly Ernest had. I have had systems that did require specific CAS ratings for the RAM.

    Chas

  • +
    0 Votes
    HAL 9000 Moderator

    Try reposting this in the 'Q&A' forum. The 'Discussion' forum is for matters of general discussion, not specific problems in search of a solution. The 'Water Cooler' is for non-technical discussions. You can submit a question to 'Q&A' here:

    http://www.techrepublic.com/forum/questions/post?tag=mantle_skin;content

    There are TR members who specifically seek out problems in need of a solution. Although there is some overlap between the forums, you'll find more of those members in 'Q&A' than in 'Discussions' or 'Water Cooler'.

    Be sure to use the voting buttons to provide your feedback. Voting a '+' does not necessarily mean that a given response contained the complete solution to your problem, but that it served to guide you toward it. This is intended to serve as an aid to those who may in the future have a problem similar to yours. If they have a ready source of reference available, perhaps won't need to repeat questions previously asked and answered. If a post did contain the solution to your problem, you can also close the question by marking the helpful post as "The Answer". .

    However in the mean time The RAM should work OK but it may not necessarily be any faster. It all depends on what the M'Board can use and the FSB of the CPU. If the M'Board can not use the faster RAM it's not going to improve performance and if the FSB of the CPU itself doesn't suit 800 MHZ RAM in Dual Chanel Configuration the System is going to run at what the CPU can support.

    So yes you should be able to used Matched Sets of RAM with the faster speed but it doesn't mean that the system is going to be any faster unless you increase the amount of RAM fitted. Even they it will just seem to perform faster but not actually run the internal commands any faster, you'll just be reaping the benefit of More RAM.

    +
    0 Votes
    CharlieSpencer

    Both of these major RAM manufacturers have utilities on their web sites to help you. Download the apps and they will tell you what you have, how much you can add, and the exact part numbers you need.

    +
    0 Votes
    NickNielsen Moderator

    Your processor and the memory control chips are what determine the speed of your memory buss . Installing faster RAM will not result in increased performance; the RAM will simply run at the lower speed.

    On the other hand, installing slower RAM will reduce performance, and can result in unreliable operation.

    +
    0 Votes
    Deadly Ernest

    speed unless the FSB can handle a higher speed too.

    +
    0 Votes
    NickNielsen Moderator

    "Installing faster RAM will not result in increased performance..."

    I might could have worded it better, though.

    +
    0 Votes
    NickNielsen Moderator

    that the faster RAM is on sale for a lower price than the specified RAM.

    +
    0 Votes
    Deadly Ernest

    being in other areas than FSB.

    Another to to watch out for is I once had a board where you HAD to match the RAM speed to the FSB or it didn't work right, never could work out why, but put in slower or faster RAM and it didn't all register - was real weird. I lived with that for a few years until I upgraded.

    +
    0 Votes
    TheChas

    I may have stumbled upon this too late for my comment to be of value.

    Anyhow, check the specifications closely as faster RAM may actually run slower if you cannot match the required clock speed for the faster RAM.

    Why?
    Most of the time, faster RAM has a higher CAS latency number and can take more clock cycles to actually respond to data changes and queries.

    The CAS rating can also explain the issue that Deadly Ernest had. I have had systems that did require specific CAS ratings for the RAM.

    Chas