Memory Upgrade Problems

Hi all,

So I'm hoping for some help with a memory upgrade problem I'm having, I haven't done a memory upgrade in a few years and it appears that I should've done more research than I did.... :??:

Anyway my problem is this:

I have a Asus P7P55d Motherboard. It had 2 x 2GB of G.Skill DDR3 DIMMS already installed.

I bought this memory which is 2 x 4GB of Crucial Ballistix DDR3 DIMMS.

I installed the two types alongside each other, hoping to achieve a total of 12GB of memory, I wasn't too bothered (rightly or wrongly) whether the full speed of the newer memory was achieved. Instead my system sees only 8GB of memory and appears to believe that it has 4 x 2GB DIMMS installed. The Crucial memory checker seemed to state that my board would support up to 16GB of memory in 4 slots, and that this memory was perfectly compatible with my current system.

My question is why is this happening? Also I'd love some opinions on what my best course of action is to utilise the memory I have... I realise this may involve ebaying some memory!!

Also I'd be happy to give anymore relevant info that may help....

12 answers Last reply
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  1. Welcome to Tom's Forum! :)

    This could be happening for a few reasons: 1. Windows 7 Home Basic is limited ti 8GB; 2. Mix-Matching the RAM Frequency, CAS Timings, Voltage and etc. ; 3. Mixing DIMM Slots incorrectly.

    Q - What OS?
    Q - What EXACT G.SKILL Set? Post a link.
    Q - What RAM is in what DIMM Slots?
  2. Thanks!

    In answer to your questions:

    1. Windows Home Premium 64bit

    2. G.Skill F3-12800CL8-2GBRM is the part number, according to a sysinfo tool I'm using, I can't seem to find any links that provide more info, but I can give all of the specs according to my tool if helpful... I think the crux of it is:
    2048MBytes, DDR3 (PC3-10700H) 667MHz (DDR3 1333)

    3. I have two channels A and B - the new memory is in channel A, specifically slots A1 and A2 and the G.Skill is in slots B1 and B2

    The motherboard manual appeared to recommend this configuration of DIMMs to slots....
  3. Those are two radically different sets and not really compatible, and at best the following 'might' get both sets to work. The Crucial you selected are the worst DDR3-1600 CAS Timings I've seen.

    1600 10-10-10-28-2N @ 1.50v 8GB (2x4GB) BL2KIT51264BA160A
    1600 08-08-08-24-2N @ 1.60v 4GB (2x2GB) F3-12800CL8D-4GBRM ;
    1600 10-10-10-28-2N @ 1.55v~1.60v

    1333 9-9-9-24-2N @ 1.55v~1.60v

    CPU: | A2 | A1 | B2 | B1 |
    New = Blue slots A1 & B1
    Old = Black slots A2 & B2

    Channels A & B must be the same capacity and keep each set in one color slots.

    AI Overclock Tuner -> Auto
    DRAM Frequency -> DDR3-1333MHz
    DRAM Timing Control -> {Depending on your options Manual, All, etc}
    DRAM CAS Latency -> 9
    DRAM RAS to CAS -> 9
    DRAM RAS PRE -> 9
    DRAM RAS ACT -> 24
    DRAM Timing Mode -> 2
    DRAM Voltage -> 1.55v

    Save & Exit = Yes

    CPU-z 'SPD' tab on both sets CAS timings would be helpful e.g. Frequency ~667MHz and corresponding timings -- USE the WORST (Highest) of each set. CPU-z ->
  4. Ok, that all looks very helpful... I'll give the config you've suggested a go.

    Out of interest do you think I would just be better off returning the new memory and buying something more compatible with my existing DIMMS? That's probably still an option at this stage.
  5. Yep, sure get the SAME Frequency, CAS Timings, Voltage and type IC's {including Brand}.

    Q - Does this 'look' like what's installed? -> On the sticks themselves there should be a 'Set Part Number.'
  6. Ok so I've set the config you've suggested and no luck as yet - still displayed as 8GB total, and all DIMMS are identified as 2GB in cpu-z.

    I've just taken a screenshot of the cpu-z info you asked for side by side for two of the DIMMS here.

    Also, yes that does look very much like what is installed.

    Thanks very much again for the help, it is appreciated. I think based on what you've said I've made an error with this purchase and should've done a better job with the research prior - it was one of those foolish pay-day spur of the moment things.

    I'll check the sticks themselves for the 'set part number' you mention next time I open it up.
  7. The BL25664BA160A.16FG are 2GB per stick...??? Maybe someone miss-packaged them?
  8. jaquith said:
    The BL25664BA160A.16FG are 2GB per stick...??? Maybe someone miss-packaged them?

    Haha - now you point it out that does appear to be the case! I hadn't picked up on that. Well I guess that means I'm definitely returning them!!

    Thankyou so much! At last I have an explanation, other than (or maybe in addition to?) my obvious incompetence, as to what is going on.

    I can't thank you enough, I'll check the part number on my other existing memory and buy some more G.Skill memory that matches CAS timings etc to go with it.

  9. IF you plan on keeping the G.SKILL, I hate tossing stuff, then look at DDR3-1600 CAS 8-8-8-24-2T {aka 2N} @ 1.60v. IF going DDR3-1333 then 8-8-8-24-2T {aka 2N} @ 1.50v and set the CAS manually. If the RAM can run CAS 8 at 1600 it sure the hell can run at 8-8-8-24 or probably CAS 7-7-7-21. The set you want is the G.SKILL F3-12800CL8D-8GBRM ->

    DDR3-1333 settings:
    DRAM CAS Latency -> 8
    DRAM RAS to CAS -> 8
    DRAM RAS PRE -> 8
    DRAM RAS ACT -> 24
  10. I'm the same, whilst I have the slots I'd ideally like to keep the G.Skill, unless it turns out to be too difficult to buy compatible stuff.

    I was just looking at that set, I'm struggling to find it available to purchase though, except at ~£140... Is this equivalent: G.SKILL F3-12800CL8D-8GBXM ?

    The only difference as far as I can see is it appears to be designed for a newer Motherboard Chipset, will that have an impact on performance or stop it working altogether?
  11. Hmmm maybe not, I seem to be able to get it for around the £80 mark, more than I intended to pay, but not too bad. Still not as cheap as the newer set though!
  12. The Ripjaws X use a different IC 'but' they 'should' work together 'but' you'll need to over-volt +0.10v for them to run together at Rated DDR3-1600 speeds. IMO - the F3-12800CL8D-8GBRM is the safer option. The performance difference between the Ripjaws X and what you have are insignificantly small, but the JEDEC 'SPD' and Voltages are different.

    My experience is 'today' mixing, any mixing, makes it a gamble to achieve Rated Frequency > 1600MHz.

    So #1 Choice = F3-12800CL8D-8GBRM and #2 Choice = F3-12800CL8D-8GBXM

    edit: Don't use XMP and set the RAM manually as above.
    AI Overclock Tuner -> Auto IF CPU >2.66GHz
    AI Overclock Tuner -> DOCP otherwise
    DRAM Frequency -> DDR3-1600MHz

    Good Luck! :)
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