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What speed RAM do I need to overclock an I5-750 to 4GHz

I am planning to buy a Gigibyte GA-P55A-UDP4 motherboard with an Intel Quat I5-750. I plan to use a CORSAIR Cooling Hydro Series CWCH50-1 cooler and overclock to 4GHz. I have a few open issues:

Please recommend the RAM speed point I should buy? DDR3 1600 through 2200 seem like the same parts with the OEM just changing the delay times. for example the DDR3 2000 (9-9-9-30) might be the same part as DDR3 1600 (7-7-7-24 ). Can someone clarify how the timing numbers affect th overall speed of the PC?

Also, Please recommend a process for achieving a stable 4GHz system?

Thanks in advance - Lee
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  1. Best answer
    you want DDR3-1600, here's why:

    at stock base clock of 133 and mem multiplier of 8 (8 x 133 = 1033 Mhz memory speed)
    at over clock BCLK of 200 and mem multiplier of 8 (8 x 200 = 1600 Mhz memory speed)

    Lowest CAS you can afford. CAS is basically the time that the memory waits between instructions...smaller numbers mean less "time sitting around w/ feet up on desk doing nothing" :)

    http://en.wikipedia.org/wiki/CAS_latency

    CAS 6 option w/ 6-8-6-24 timings $160
    http://www.newegg.com/Product/Product.aspx?Item=N82E16820226120

    CAS 7 Option w/ 7-9-7-24 timings $105
    http://www.newegg.com/Product/Product.aspx?Item=N82E16820226103

    CAS 8 Option w/ 8-8-8-24 timings $88
    http://www.newegg.com/Product/Product.aspx?Item=N82E16820227483

    CAS 9 Option w/ 9-9-9-24 timings $70
    http://www.newegg.com/Product/Product.aspx?Item=N82E16820227495


    Gigabyte's implementation of USB 3 cripples PCI-E slot....suggest you read this article

    http://www.tomshardware.com/reviews/usb-3.0-performance,2490.html

    Asus alternate
    http://www.newegg.com/Product/Product.aspx?Item=N82E16813131621

    This is for the i7 so I don't know how well it will jive but it's the best OC Guide I have found yet.
    http://vip.asus.com/forum/view.aspx?SLanguage=en-us&id=20081220191040237&board_id=1&model=P6T%20Deluxe&page=1&count=66
  2. Hi lee,

    You will want 1600mhz or more to get to 4ghz. 1600 mhz ram is usually the same thing as 2200mhz ram, it is just a better batch. Think of it like a i7 920 vs an i7 975.

    CAS timings affect the speed of the system very little, but lower times generally means a faster PC.

    You will want to google for an overclocking guide on the i5, nobody is going to write you one up right here.

    Hope that helps...
  3. Beat me to it jack :lol:
  4. well ya don't give me that opportunity often :)
  5. Thanks for all your answers it helped alot - Lee
  6. The RAM multiplier options of i5-750 are 6x, 8x and 10x and so you want to get a RAM that can run at spec with your current BCLK and available multiplier.

    Hence, your choices are:
    (with 4GHz=200x20 CPU frequency)

    1600MHz=200x8
    2000MHz=200x10

    In addition, lower frequency RAM are usually with lower latency too which is better than RAMs that have higher frequency and higher latency.

    Thus, 1600MHz ram is your best choice.

    I would get a 1600MHz & CL8 RAM, because it has the best cost-performance ratio.

    However, don't be hesitate to go for CL6 and CL7 if they are only a few dollars more than CL8 one.
  7. Everyone - thanks for your answers. I have the info I need. Since I am new to this forum how do I close this thread?

    Lee
  8. You can't and only mods are able to do that.
  9. Best answer selected by Lee Gordon.
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