MA790FXT-UD5P Ram help

Hi all,

My setup is as follows:

Gigabyte MA790FXT-UD5P
AMD Phenom II x4 955 BE
Sapphire ATI Radeon HD 4870
OCZ 4GB PC3-12800 EB Platinum Edition (purchased from ebay)

the problem is that when I look on the motherboard compatability list, the memory I purchased is not shown as compatible.

Does this mean the memory will simply not work?

I see the abbreviations for timings on the OCZ DDR3 PC3-12800 Platinum Edition product description page as CL 7-7-7-24
(CAS-TRCD-TRP-TRAS) 1.7volts

but the ebay listing has it set as
CL 7-7-6-24 (CAS-TRCD-TRP-TRAS) 1.8-1.95*** Volts EVP***

in my BIOS i have the following adjustable settings in DRAM configuration (the values that the BIOS has 'optimally loaded' are in the parenthesis):

CPU frequency(200Mhz)
Memory Clock [x6.66] (1333mhz)
DTCs Mode (ungaged)
Cas# latency (7t)
RAS to CAS R/W Delay (7t)
Row Precharge Time (7t)
Minimum RAS active time (30t)
1T/2T Command timing ( --)
TwTr Command Delay (5t)
Trfc0 for DIMM1 (110ns)
Trfc0 for DIMM2 (--)
Trfc0 for DIMM3 (110ns)
Trfc0 for DIMM4 (--)
Write recovery time (10t)
Prechage time (5t)
Row cycle time (28t)
RAS to RAS delay (4t)
CHA Proc0dt (60 ohgms)
CHA DQS drive strength (1.0x)
CHA Data drive strength (1.0x)
CHA MEMCLK drive strength (1.5x)
CHA Add/Cmd drive strength (1.5x)
CHA CS/ODT drive strength (1.5x)
CHA CKE drive strength (1.5x)
CHB Proc0dt (60 ohgms)
CHB DQS drive strength (1.0x)
CHB Data drive strength (1.0x)
CHB MEMCLK drive strength (1.5x)
CHB Add/Cmd drive strength (1.5x)
CHB CS/ODT drive strength (1.5x)
CHB CKE drive strength (1.5x)
Bank interleaving (enabled)
Channel interleave (enabled)
DQS training control (Skip DQS)
CKE Power Down Mode (Disabled)
Memclock tri-stating (disabled)

Can someone please tell me which settings to change, and what to change them to?
or if I shouldn't even bother, because the RAM simply will not be compatible.

I would really like to avoid having to return/resell this ram, but if there is no other option - I supposed I would have to.

Thank you for any help!

12 answers Last reply Best Answer
More about ma790fxt ud5p help
  1. hi i have the same setup but 8Gbs of ram instead of 4 and they work fine... strange how they dont work with you... i changed the timmings to match the timmings they're rated for, but even before that, they worked fine... i dont think changing things in the bios well help yo much :S might be something with the ram.... try testing it on another machine or something... :s (btw they arent in the compatibility list but i assure you they work :S)
  2. Try to load defaults in bios the ram should work just fine.

    I didn't really get if you really have problems with the ram, can your pc boot and is it stable? if so don't bother with the timings
  3. Best answer
    the problem is that when I look on the motherboard compatability list, the memory I purchased is not shown as compatible.

    Does this mean the memory will simply not work?

    Lots of memory that will work never makes the approved list - it's endemic to the industry. For GBs, what happens is the approved memory list is made up when the MOBO is introduced from sticks they have been provided samples of, and never updated thereafter; in addition, many of the memory manufacturers that you'll see there you've never heard of, as (and I've said this before) I'm sure you can pick them up at any gas station in Taiwan, but they're not to be had here. That's also why, for a lot of boards, there are scads of 512M and 1G sticks, but few 2x2s and 4x2s...

    Overall - don't worry about it - do the "Load Optimized Defaults", and if it works OK - you're good!
  4. ok sweet. it is working - i just wasn't sure if this could be causing my problems with windows intallation.

    Thanks so much for the help guys!
  5. I think You have diferent sticks... from your first info I assume that You have
    I have same Mobo and this sticks and i run them @ 7-6-6-24 with 1.9V
    Anyway Ill join you with your question what are all that settings in BIOS, some of them arent even in manual.
  6. Oops, typo: 7-7-6-24-27
  7. For a quick rundown on 'what is all this stuff':
    For a more comprehensive look, try "What Every Programmer Should Know About Memory" that I've placed here:
    It's long (114 pages!), but thorough; I'd suggest 'skimming' chapter one (the 'intro') for its 'gist'; chapter two is the 'real meat' - the physical operation... Three is more to understand CPU selection, as it describes cache, organization, 'snooping' and the like, and the rest (except for the last chapter, which is interesting in a 'scifi' sort of way, concerning possible new technologies on the horizon...), unless you're writing programs, can be ignored!
  8. bilbat: Thank You ;)
  9. yeah, that is some serious tech bilbat!

    right up my alley, thank you.
  10. Only last 4 remains:
    Bank interleaving (enabled)
    Channel interleave (enabled)
    DQS training control (Perform DQS)
    CKE Power Down Mode (Disabled)
    Memclock tri-stating (disabled) - I dont rly inderstand what this do

    Googled all of them, but have found only theoretical info, no practical usage on MA790FXT-UD5P.
    I dont rly inderstand what Memclock tri-stating do exactly... on my system i cant boot OS with "enabled".
    Anyone have idea what is best setum of these 4? I use these settings ^
  11. OK - I can't be particularly helpful here, at least from a firmly established hardware oriented basis - 'cause, as usual, it appears to be top-effing-secret! To start out, I spent nearly an hour casting around to try to get some documentation; searching AMD tech doc database turned up exactly one item for the 790FX chipset:
    Read it and weep (literally!)! And then people criticize me for criticizing AMD and their lack of publicly available documentation, and likening the difference between Intel docs and AMD docs to, sort of, microns and light years!

    Interleaving is, generally speaking, a good thing, and you want it happening whenever possible; I have been told that this idea has led me to a mistake in setting up AMD CPU/chipset combos with selectable DCTs Mode; I automatically assumed that 'ganged' (dual-channel) would be faster, due to interleaving - but, I have been told (but, unfortunately, not shown any numbers) that this is not always so... I would leave it enabled for both bank and channel... For a bit more technical treatment, you could give this a read:
    It's a bit dated, but will give you the general idea...

    As for DQS training, I found an old, old (had an AGP bus!) AMD doc that described a precursor to this, and, if they are at all like Intel, once they latch onto a design feature, my guess is they'll stick with it until it becomes totally obsolete - simply adapting the technology to faster and faster operation... The chipset contains programmable delay lines, that can be physically 'adjusted' to match RAM timing elements; these PDLs can be trained, to 'wobble', and observe the results, in order to more closely match the actual physical layout of the DIMMs, and the 'meander' of connection lines to them... The chipset can then be programmed to periodically ( like, every ten to the seventh, eighth, or ninth clock cycles) 're-train' their circuitry, but I could not figure out, from the available documentation, why this would be desirable; I also have to assume this 'disables' the memory circuitry for the amount of time it takes to 'wobble and home in on' these settings... I can't imagine that temperature would 'shift' the underlying impedances (loads) of the RAM access circuitry enough to make this necessary, and I don't know why else you'd do it... Short of trying it both ways, and running some 'synthetic' memory benchmarks at each setting, my advice here would be to disable...

    CKE power down, I believe, will depend on which 'sleep state' you've enabled; if you're using an S1 sleep (power-on suspend), leave it disabled; if you intend to S3 (suspend to RAM), you probably want it enabled - again, best thing is to test - whether, and how quickly, you can 'wake up' a 'sleeping' machine; if you're like me, and leave all the 'green crap' turned off - won't matter!

    Re 'tri-stating', the underlying idea is explained fairly clearly here:
    What it's doing on this board is anybody's guess - the only place I've ever heard of tri-stating a memory bus is on multi-processor server board, and it's pretty much been superceded by having each processor 'hooked up' to its own memory banking, and then 'hyper-transporting' blocks back and forth... I imagine this is in the top-secret, eyes-only, need-to-know basis, NDA-required, "once you read this, we have to sew your lips shut", AMD AGESA processor start-up documentation - I used to know somebody who had a copy, but I think he's in a prison camp on Titan!
  12. Thanks tilbat again, you certenly spended lot of time on my request :D
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