1600 Memory but ASUS says its latency is 1066


I'm building a system where the motherboard supports 1600 memory speed without overclocking. I am looking at ASUS' compatible memory list so I can make sure I get maximum speed. I do not overclock...

The memory I want to buy has this in the latency column: "8-8-8(1066-7-7-7-20)"

Does this mean it is going to run at 1066? Not sure what the point of that is. There doesn't seem to be many on the list that are both listed as 1600 and have latency settings at 1600.

What does this mean?
13 answers Last reply Best Answer
More about 1600 memory asus latency 1066
  1. Need to know (2) pieces of information:
    1. What MOBO model?
    2. What DDR part-number?
  2. Absolutely

    Mobo: ASUS P6X58D-E
    Memory: Gold XTC 6GB DDR3-1600 (PC3-12800) CL8 Memory Kit (Three 2GB Memory Modules)
  3. I have the same MOBO for our office - good MOBO. I originally misread - "I want to buy"

    Is this the EXACT DDR3 -

    Easy: 1600Mhz is native support speed.
    When installing verify that the DDR3 is located on A1 B1 C1 slots. If the link is 100% correct then set the DRAM Freq 1600 in the BIOS, Exit & Save.

    Review and download the {Memory Support List} -

    My favorites are {Corsair, G.SKILL, Mushkin & Kingston} but OCZ is a good brand.
  4. Yes that's it, but ASUS documentation says this:

    DDR3 1600
    6GB(3 x 2GB)
    Heat-Sink Package

    See how for latency it says 1066. Why isn't it saying 1600, will it run slower? I don't want to have a support problem right off the bat and have it running at 1066. Unless this means 2 different things. They do have other models on the list that say 1600 for latency but I can't find them to purchase.
  5. Best answer
    Okay, now I understand what you're asking.

    Yes, the higher 1600 MHz indeed causes the latency to get higher {slower} 8-8-8-20 vs 7-7-7-20 - this is a trade-off with ALL DDR, but the CAS of 8 @ 1600 MHz is a better trade than a CAS of 7 @ 1066MHz. I "prefer" CAS 7 @ 1600MHz, but the difference is negligible in the "real world."

    link -

    (CAS ÷ DATA RATE) × 2000 = X ns
    (7 ÷ 1333) × 2000 = 10.5026 ns

    Low CAS and High MHz is po$$ible, but expensive.

    By default, Certified memory of ASUS recognized DDR3 will be set at the rated 1600 MHz CAS 8-8-8-20, so you can set the DRAM Freq also to 1066 MHz for the lower CAS.

    "Why isn't it saying 1600, will it run slower?" = 1600 is the rated speed, and yes it can run slower as under-clocked.

    "I don't want to have a support problem right off the bat and have it running at 1066" = that DDR is Certified to work and it will work at either speed without problems; except if there's a Mfg defect.

    Again, the Certified DDR3 is the "best" choice -

    OCZ Tested -
    1GB, 1600MHz, DDR3-1600 PC3-12800, 240p DIMM, 1.5v OCZ316001G
    2GB, 1066MHz, DDR3-1066 PC3-8500, 240p DIMM, 1.5v OCZ310662G
    2GB, 1600MHz, DDR3-1600 PC3-12800, 240p DIMM, 1.5v OCZ316002G
    4GB, 1066MHz, DDR3-1066 PC3-8500, 240p DIMM, 1.5v OCZ310664G
    4GB, 1600MHz, DDR3-1600 PC3-12800, 240p DIMM, 1.5v OCZ316004G

    This should answer your questions.
  6. Cool thanks. So here is the real question.

    If the step-down mobo is 1066 max for memory and I don't care about its lesser features, should I go for that instead. Or will the 1066 mobo operate at an even slower CAS

    With rebate this mobo is $60 cheaper: P6T LGA 1366 X58 ATX Motherboard
  7. The Real Answer - is not to purchase a MOBO based upon supported DDR speeds. You can OC the MOBO to work perfectly well at 1600 MHz.

    6 x DIMM, Max. 24 GB, DDR3 2000(O.C.)*/1866(O.C.)*/1800(O.C.)*/1600(O.C.)/1333/1066 Memory

    Round-down (DDR Speed 1600 / BCLK = 133.33) = Memory Multiplier 12
    Round-down (DDR Speed 1066 / BCLK = 133.33) = Memory Multiplier 10 8
    Configure ALL DDR CAS 8-8-8-20

    Therefore, a Memory Multiplier of +2 and the ASUS or any MOBO will run at full speed and correctly set w/o a hitch.
  8. Cool thanks.

    On 2nd though just read a bunch of bad reviews on the P6T LGA 1366 X58 ATX Motherboard. Someone mentioned issues with 64 bit which makes me nervous. The whole point of this is to build a 64 bit system.
  9. Best answer selected by bugmenot1983.
  10. ^ I thought I mentioned I have 9 - ASUS P6X58D-E for my office after returning 9/10 GA-X58A-UD3R (rev. 2.0) that Tom's proclaimed to be so great. {SSD + RAID 1 - new confirmed issue}

    So there are a few things to learn 1. Get a very good MOBO; I highly recommend ASUS P6X58D-E, and 2. a very good PSU; I highly recommend Corsair {single (1) rail + Japanese capacitors}, and 3. don't let a few bucks saved = years of hell + aggravation.
  11. yea im gonna go with a Antec Earthwatts 750W ATX Power Supply. Its continuous power and supposed to be efficient power consumption. I leave my pc on all the time cuz it downloads stuff and is also a web server.

    What cooler did you go with for your processor? I'm going i7 930 which runs hot, so I want to get something good.
  12. Thanks, these look like solid options. I don't understand the concept of rails fully even after reading the wiki, but I'll take your word for it.
Ask a new question

Read More

Memory Overclocking Latency Asus Product