Asus P7P55D-E, Core-i5 750 and 16gb(8gb usable)?

I have a problem, I5-750, asus p7p55d-e, Kingston Hyper X Genesis 4x4GB, DDR3 1600MHz, CL9.

My win7 64bit ultimate says "Installed memory (RAM): 16,0 GB (8,00 GB usable)"

What's happening? I updated my bios couple of weeks ago, dunno if there's a new one out.

When i boot, the post says 8gb of ram which is also weird.

Help please.
27 answers Last reply
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  1. Welcome to Tom's Forum! :)

    First off if for some reason you have Windows 7 Home Basic, I noted Ultimate, the maximum would be 8GB even with 64-bit.

    Q - What exact set of RAM do you have? Provide a link. Possibility it's the (KHX1600C9D3K4/16GX) kit but I need to know 100% before posting BIOS settings.

    As in the last post, the RAM needs to be properly seated. Further, in MSCONFIG verify the following settings:


    Next, look at the Resource Monitor; if the Hardware Reserved > 8000MB then the BIOS is shutting-down 2 of the 4 sticks. Typically this is a DRAM and/or QPI/VTT Voltage issue.
  2. Hello jaquith, thanks for quick response.

    My ram is http://www.jimms.fi/tuote/KHX1600C9D3X2K2/8GX, i've got two of these 2x4gb kits.

    Resource Monitor says "Hardware reserved 8194 MB".

    My win7 is the ultimate version.
  3. KHX1600C9D3X2K2/8GX - http://www.valueram.com/datasheets/KHX1600C9D3X2K2_8GX.pdf

    DDR3-1600 9-9-9-27-2N @ 1.65v
    CPU Intel® Core™ i5-750 Processor (2.66 GHz) ; minimum BIOS 0304 ; recommended BIOS 1504


    BIOS:
    AI Overclock Tuner -> DOCP
    DRAM OC Profile -> DDR3-1600MHz
    DRAM Timing Control -> Manual
    -
    DRAM CAS -> 9
    DRAM RAS -> 9
    DRAM RAS PRE -> 9
    DRAM RAS ACT -> 27
    -
    DRAM Timing Mode -> 2N
    -
    IMC Voltage -> 1.25v~1.30v ; start with 1.25v if the 8GB vs 16GB problem persists 1.30v~1.35v max
    DRAM Voltage -> 1.64v~1.67v ; start with 1.64v if the 8GB vs 16GB problem persists 1.65v~1.67v max

    Save & Exit = Yes

    Boot

    1. Open Resource Monitor and see if all 16GB shows-up
    2. Install/run CPU-z and click on the Memory (tab) should show DRAM Frequency = 800MHz (DDR Double Data Rate = 1600MHz), 9-9-9-27-2N
    CPU-z download -> http://www.cpuid.com/softwares/cpu-z.html

    Example (DDR3-1600, 9-9-9-24-1T):
  4. I've now tried with the bios settings and dram timings given, voltage settings i tried as follows:

    IMC Voltage 1,25v, Dram Voltage 1,65 result 8gb hardware reserved.
    IMC Voltage 1,275v, Dram Voltage 1,65 result 8gb hardware reserved.
    IMC Voltage 1,30v, Dram Voltage 1,65 result 8gb hardware reserved.
    IMC Voltage 1,30v, Dram Voltage 1,6625 result 8gb hardware reserved.
    IMC Voltage 1,325v, Dram Voltage 1,6625 result 8gb hardware reserved.
    IMC Voltage 1,35v, Dram Voltage 1,6625 result 8gb hardware reserved.

    I didn't go any higher on dram voltage since the next increment would've been 1,6750v and 1.67 was the max you gave me.

    I also tried with the X.M.P. profile and it yealded the same 8gb hardware reserved result.

    CPU-z showed the correct values on the memory tab.

    What do you think would be my next option?

    I read on some topic that someone recommended me to take my cpu and cpu-cooler off and reseat my cpu and cpu-cooler for it might be "off"? I do have a Noctua NH-D14 which is wound up pretty tightly, what do you think?

    It's a bit odd though due my pc seems to know 16gb of ram is installed, so i personally don't see how it could be an issue of something not beein fitted correctly.
  5. Once in a while the P55/LGA 1156 can have a bent CPU pin which effectively yields 1/2 the RAM. The HSF might be the root cause, but IMO try the following 'easy' approach 1st. Failure below - try the stock HSF; I assume that you have more Thermal Paste because you'll need if IF you ever used the stock HSF <or> if you remount the Noctua.

    DRAM 1.65v + IMC 1.30v is the 'typical' voltages.

    A. Testing DIMM Slots:
    1. Note may not boot ; DIMM bank2:
    CPU: | RAM | blank | RAM | blank |
    2. Musical DIMM Slots Set1 <=> Set2 ;
    CPU | Set2 | Set1 | Set2 | Set1 | => CPU | Set1 | Set2 | Set1 | Set2 |
    3. Set1 only ; CPU: | blank | RAM | blank | RAM |
    4. Set2 only ; CPU: | blank | RAM | blank | RAM |

    B. However, if the above fails then rule-out a DIMM or other short/grounding short:

    You can try Lazyman's Breadboard -
    * Disconnect ALL Front Panel & USB Headers ; keep only the PWR & Ground aka Power Button
    * Disconnect ALL peripherals except the Keyboard/Mouse
    * (4) Sticks of RAM ; CPU | Set2 | Set1 | Set2 | Set1 |
    * Unscrew both the MOBO and PCIe screws

    Pull the MOBO away from anything conductive and supported by a towel ; Boot.

    C. Stock HSF an look for bent CPU Pins ; you'll need a magnifying lens to see and Jeweler's tweezers to straighten.
  6. Hi,
    I have nearly the same setup and the same issue: http://www.tomshardware.co.uk/forum/298149-12-16gb-p7p55d-usable#t2046477

    Since i haven't got any internets for my pc yet, i will try to dismantle it and make a provisorisk test-bench ^^

    The worst will be to try to get that noctua of the board.

    @jaquith, where did you find the bios settings for the ram?
  7. Squall321 said:
    @jaquith, where did you find the bios settings for the ram?

    Just know them. You need to know both your CPU and RAM...lot's of posts and building experience.
  8. I have experience with latencies, but i have never "played" with voltages.(My recent tries with adjusting the voltages did result in crashes)..
    So i will go with the failsafe-non-tampered settings for the ram's while doing the test
  9. Over voltage or under voltage are equally unstable. The reason I have no choice but to provide a range is because no 2 CPU's or MOBO behave exactly the same. Further, if you don't know or get confused what volatge is what then sure you'll have a problem.

    Example the CPU's IMC voltage (QPI/VTT/VCCIO/IMC...) has many names on different CPU's and MOBO's -- heck I've caught myself accidentally, on AMD, posting the wrong voltage name; right voltage wrong name.
  10. it's those names, that confuse me(IMC for example).
    yea i see, that i got the problem to not to know, what voltage is the right voltage to work on.
    just to know what "line" gives power to what..

    Edit:
    back to topic, i have opened some cpu-z windows to take screenshots yesterday. but when i had opened the third window, i suddenly saw, that my RAM went from before shown 16gb to 8gb.
    in the first windows i could see each RAM-module in the SPD-tab, but later, when it only showed the 8gb, the SPD-tab was empty.

    and offcourse i forgot to take the screenshots -.-'
    today, cpu-z is only showing the 16gb all the time..

    (and to that voltage thing, i will google my way through it and learn it somehow.)
  11. CPU-z is NOT a good indicator of 'Functioning' RAM, but it's a good indicator of 'What's' installed and the component attributes. As shown above, it best to use Window's 7 Resource Monitor and in particular look at the Hardware Reserved aka held back by the BIOS.
  12. here:
  13. Yep, the BIOS is shutting down 1/2 your RAM. Again, on LGA 1156 it's also common to have a bent CPU pin.

    Q - What exact kit(s)? ; I prefer a link.
    Q - What if any BIOS changes?
    Q - What MOBO?
    Q - What CPU?
  14. RAM: http://www.corsair.com/memory-by-product-family/vengeance/vengeance-low-profile-blue-16gb-dual-channel-ddr3-memory-kit-cml16gx3m4a1600c9b.html

    mobo/cpu: http://valid.canardpc.com/show_oc.php?id=2184642

    bios, xmp-profile

    so you mean i should go down and look on all the 1156-pins on both the cpu and mobo to be sure, that would be 2312 connections i should look after. but if i remember properly, there weren't any pins but "pads"

    i actually get excitet looking at this close-up: http://images.bit-tech.net/content_images/2010/10/intel-core-i5-760-review/core-i5-760-2-l.jpg
  15. The RAM is DDR3-1600 9-9-9-24-2N @ 1.50v.

    BIOS:
    AI Overclock Tuner -> Auto ; 2.8GHz CPU
    DRAM Frequency -> DDR3-1600MHz
    DRAM Timing Control -> Manual
    -
    DRAM CAS -> 9
    DRAM RAS -> 9
    DRAM RAS PRE -> 9
    DRAM RAS ACT -> 24
    -
    DRAM Timing Mode -> 2N
    -
    IMC Voltage -> Auto
    DRAM Voltage -> 1.50v~1.55v ; start with 1.50v if the 8GB vs 16GB problem persists 1.55v max

    Save & Exit = Yes

    The CPU doesn't have the pins, the pins are located on the MOBO itself.
  16. Thanks.
    i tried all of the before mentioned settings and voltages(since there was only possible to do 0.02 increments, i went from 1.5 to 1.56).

    the problem persists.

    currently running D.O.C.P profile with the only set voltage of 1.56 on the rams. and set my multiplier to 21 again. for an insanely 500mhz oc on the cpu :P

    still 8gb hardware reserved.

    i've been around the forums and found this:
    "If you put a pair of memory that designed to work only on channel 1, on channel 2 (like I did unknowingly). The Bios only recognizes them, "BUT" not made available to use.
    Windows 7 can only see the total ram installed (in my case 8GB), but can't make use of the other 4GB on memory channel 2, and
    Windows 7 thinks the 4GB memory are "HARDWARE RESERVED"."

    could this be true?..

    (i should get my lazy a** up and dismantle the pc and try it, but this thing is my one and only... shutting it down and work on it would seem to be a pain.)
  17. The OP needs DOCP, you do not. In fact it's a problem; you have a 2.8GHz CPU review this again - http://i1013.photobucket.com/albums/af254/Jaquith/266DOCP.jpg

    IMO Load Defaults then boot check HW Reserved, and then only enter the BIOS values I posted above and check again.

    An alternative is to try XMP; I also assume the RAM is indeed properly seated in the DIMM slots.

    Alternative BIOS (XMP):

    Load Defaults
    AI Overclock Tuner -> X.M.P. ; this assumes a single kit of 4x4GB
    eXtreme Memory Profile -> Performance

    Save & Exit = Yes
  18. it was a hardware problem!


    al i did, was to turn of the system off(oh teh pain)!, plugged the power cable, removed the 8pin-cpu power cord from mb, unmount the front cooler of my noctua nh-d14 and pull all ram out.
    putting them in a different order. and making sure they sat really good.
    bam.! look for yourself on the picture. 16gb of ram installed and working as they should.!

    uber happy
    René :D
  19. I had the same setup P7P55D-E with i5 750, recently notice that it only usable of 8G where I had installed 16G (4x4G) of RAM.

    Do few testing as suggested by everyone (re-seat CPU, re-seat RAM, check BIOS setting) finally found the culprit to be one of the 4G RAM having issue.

    Replace it will another 4G RAM and I had now with 16G usable RAM.
  20. Hello, can I ask if this motherboard supports 2*8 GB RAM module? Ty in advance
  21. Squall321 said:
    it was a hardware problem!
    http://i1195.photobucket.com/albums/aa392/Squall3210/Capture.png

    al i did, was to turn of the system off(oh teh pain)!, plugged the power cable, removed the 8pin-cpu power cord from mb, unmount the front cooler of my noctua nh-d14 and pull all ram out.
    putting them in a different order. and making sure they sat really good.
    bam.! look for yourself on the picture. 16gb of ram installed and working as they should.!

    uber happy
    René :D



    ok dude could you explain this in details i dont know much about computers and i really need someones help my computer's fucked up i have 4 gigs of ram and only 2 is usable (2050 mb hardware reserved) if any pc guy can post screen shots how to do what he did i dont understand one thing of what he said it will be much appreciated or tell me what to do step by step or even link me the steps please reply
  22. noobis said:
    ok dude could you explain this in details i dont know much about computers and i really need someones help my computer's fucked up i have 4 gigs of ram and only 2 is usable (2050 mb hardware reserved) if any pc guy can post screen shots how to do what he did i dont understand one thing of what he said it will be much appreciated or tell me what to do step by step or even link me the steps please reply


    i don't know really, but if you could write up the specs of your pc, i could maybe look into it. there exists some OS specific limitations, so find out which windows you are running. motherboard brand and make. and so on.
  23. Quote:
    Hello, can I ask if this motherboard supports 2*8 GB RAM module? Ty in advance


    look into the QVL of the motherboard, to find out what memory is guaranteed supportet for the motherboard:
    http://www.asus.com/Motherboard/P7P55DE/#support_QVL
  24. I Have the same problem...

    my PC:
    Win7 ultimate 64bit
    Asus P7p55d-3 evo
    Intel i5 2,66 ghz
    4x4gb corsair vengeance lp cml8gx3m2a1600c9
    Any help ?
    Thanks in advance

    16gb installed ( 8gb usable)
  25. DaConsumarsi said:
    I Have the same problem...

    my PC:
    Win7 ultimate 64bit
    Asus P7p55d-3 evo
    Intel i5 2,66 ghz
    4x4gb corsair vengeance lp cml8gx3m2a1600c9
    Any help ?
    Thanks in advance

    16gb installed ( 8gb usable)


    Try reseating them
  26. DaConsumarsi said:
    I Have the same problem...

    my PC:
    Win7 ultimate 64bit
    Asus P7p55d-3 evo
    Intel i5 2,66 ghz
    4x4gb corsair vengeance lp cml8gx3m2a1600c9
    Any help ?
    Thanks in advance

    16gb installed ( 8gb usable)


    Try reseating them
  27. I already tried every single combination ... but it didn't work though
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