790FX-GD70 & 1090T, Issues...

[EXCellR8]

built a new computer for a friend of mine and I'm having a few issues with the motherboard and processor (and maybe the memory). the board is an MSI 790FX-GD70 and the CPU is the AMD Phenom II 1090T, the six core. i installed 8GB of Corsair DDR3 which is supposed to run at 1600mhz (8-8-8-24). everything works fine if the settings are all set to "Auto" but the memory speed and timings go out of spec: 1333mhz and 9-9-9-24. these settings however allow the computer to run just fine...

the problem arises when i try to set the CPU/DRAM ratio to 1:4 (to enable the RAM to run @ 1600mhz and stock timings). doing this causes the board to no-POST or freeze up in BIOS, and i have to clear CMOS to recover. keep in mind that i am not changing voltages or any other frequencies so this is rather strange to me. i'm not too knowledgeable with the newer AMD stuff so it's probably something simple, but i'd like to see him get the full 1600mhz if possible. any help would be appreciated, thanks!

 

[richierich1212]

Might need to add cpu-nb voltage and/or vdimm. Is it rated for 1.5vdimm? If so try 1.54vdimm.

 

[EXCellR8]

the modules are rated for 1.65v and won't go any lower than that. i suppose i could try upping it a little bit because the board may be under-powering them slightly. one thing i don't understand is the whole DC0/DC1/BOTH setting or whatever it is. i have the option to set it to auto but then i can't set the timings manually... never seen that before.

 

[Plimogz]

RE: [DCT 0], [DCT 1] or [BOTH]
From the MSI documentation:

*DRAM Timing Mode
This field has the capacity to automatically detect the DRAM timing. If you set this field to [DCT 0], [DCT 1] or [BOTH], some fields will appear and selectable. DCT 0 controls channel A and DCT 1 controls channel B.

&

*DCT Unganged Mode
This feature is used to integrate two 64-bit DCTs into a 128-bit interface

And I came across this interesting nugget on hwbot.org while searching around (for no readily explainable reason):

When setting unganged mode, you basically make the mem config 2x 64bit, so you need to have both DCT's configured. So, if you set unganged mode and want performance, you need to set the DRAM mode to 'both' and manually fix both DCT timings. If you don't, one DCT is set to SPD timings, I think.

Fixed my issues, so I asked MSI to implent a bios option that allows end users to set both by only typing in the timings manually once. a 'linked' option.

That "linked" option of which he speaks is the "[BOTH]" from your BIOS menu.

Oh, and here's an XKCD which kinda sprung to mind as I was looking around for this http://xkcd.com/903/

 

[richierich1212]

Some boards don't like that 1:4 memory divider. So unfortunately you're going to have to try increasing the HTT while lowering the memory divider so that it will run at the 1333 divider but overclocked to 1600.

I can't remember but I think either 250HTT or 300HTT yields that result. Remember to lower HT-link multi, NB multiplier and CPU multiplier back down to where you want it.

 

[EXCellR8]

Ok I will give it a try later, thanks for the responses.

This field has the capacity to automatically detect the DRAM timing. If you set this field to [DCT 0], [DCT 1] or [BOTH], some fields will appear and selectable. DCT 0 controls channel A and DCT 1 controls channel B.

Cool, that's kind of what I figured but the terminology sort of had me confused, thanks.

 

[EXCellR8]

So I tried fiddling with it for around an hour but it's not letting me do anything. I was able to get the HTT to 250 and then use a [x13] multi (x8 on the NB) but it's not stable at all for some reason. I brought the voltages up just a tad since I'm only overclocking the processor slightly and made the necessary RAM adjustments that allow for intended speed. The system either locks up or doesn't POST, or I get some kind of unknown BIOS error followed by some garbled crap. At this point I might just leave it alone because this was supposed to be a 5min tweak and I'm hours in now.

Thanks for the support though, I appreciate it.

 

[Plimogz]

Sure, giving up on the 1600MHz/8-8-8-24 settings isn't going to cause a bloody puppy massacre, but if it was me, I'd OCD the hell out of the BIOS and damn well get it to work.

So, if you're willing to give it another go, here's how I think you should go about it:

1: Get some known working settings. (i.e. get to the point where AUTO settings are fully functional in windows. -- I believe you have this for 1333MHz/9-9-9-24. with who-knows-how-much voltage -- I assume those are on AUTO withal.)

2: Figure out what precisely AUTO is setting stuff to. (The current settings should be visible somewhere in the BIOS, at least they usually are on the Gigabyte boards I've been using of late) Or install AMD Overdrive and pore over that status tab. It'll give you all the voltage and DRAM timing information you'll ever need, with extra for good measure.)

3: Get into the BIOS and enter those known working settings manually. If it was me I'd just enter the main memory timings at first and pretty much leave sub-timings on AUTO, because there's a whole lot I don't really understand about DRAM, and AUTO is practically always better than I at setting proper sub-timings.

#1-2-3 TLDR: manually set the 1333MHz/9-9-9-24 parameters, set DRAM voltage to 1.65V

4: Cross fingers, save settings and restart. If this doesn't work, you may need to figure out the BIOS menu some more. It's been years since I've played around with an MSI motherboard, but that board was a pleasure and they're a top manufacturer so I'm not quite willing to believe that yours is incapable of these basic things. Nor would I readily accept that a Thuban IMC cannot run 2 4GB sticks @1600MHz. So user error is all that's really left me...

5: Once you've got 1333MHz/9-9-9-24 dialled in, it should simply be a matter of upping the memory divisor, and then tightening the timings. I do realize that this is sometimes easier said than done, but... If it was me I'd set 1600MHz at first, leaving the slacker timings for the time being. And only after another restart/test/shutdown would I tighten the timings.

6: Should speeding up either the frequency or timings fail, I would then increase DRAM voltage 0.05V at a time. Up to a maximum of 1.75V. If then faced with a still stubbornly crashing machine, I would lower memory voltage back to stock and go about increasing CPU-NB and NB voltages a little bit. (of course, if those are still on AUTO at this point, which they well might be, you'd need to check what the known functional AUTO setting amounts to before increasing them both slightly.) Of course, if that too failed, I'd try setting all three voltages higher than stock simultaneously. Even though it seems to me that getting two sticks of 1600 to run 8-8-8 on a Thuban should require no increases of voltages, but I digress.

7: If that fails (which I suppose it well could, given that all the advice I've given you is painfully generic) you could try opening a ticket with Corsair technical support. Having no first hand experience with their products (I usually purchase OCZ memory, and have always been impressed with their technical support forum) so I can't say this from personal experience but I've gotten the impression that Corsair is a truly first rate operation, quite on par with OCZ (some might even say better), and there's probably someone there with actual experience with both AMD hex-cores and your particular memory who could help.

 

[richierich1212]

You can try the other memory slots too, sometimes that helps. But it sounds like your main problem is getting the memory timings input correctly.

 

[VirtualLarry]

If you want to run at 1600 on AMD, you have to overclock.

 

[EXCellR8]

this is probably where i should mention that all four slots are filled with 2GB sticks, but they are identical. i don't think it's the RAM as much as it is the motherboard, but i could be wrong (it's happened before).

Plim, thanks for the advice... i will give it another shot when i'm feeling up to it but i don't want to mess with it too much. last thing i need is to order new parts for this thing over 267mhz. i can tell you right now my friend doesn't give a damn about memory speed it's more me being frustrated over not being able to get it right.

 

[Plimogz]

this is probably where i should mention that all four slots are filled with 2GB sticks

Ah ha! J'accuse!
/jk

Getting 4x2GB @1600 to work is a good deal harder than 2x4GB.

In this case, you could try something along what I've outlined before, but with only one pair at a time. 'Should be a walk in the park. The comment about one pair of slots on the board sometimes being friendlier than the other is valid, albeit not much of concern when you're planning on populating all four of them anyhow.

As I was saying, put 2 sticks in there, making sure you're using a proper set of slots for dual-channel. Attempt to get 1600/8-8-8. When that works -- which it damned well should -- pull those and insert the other pair of DIMMs into the other slots -- this should also be a breeze.

Now, as I've said before, I have no experience with the AMD hex-cores, but I did spend a good while with a C3 Phenom, and am functioning under the assumption that their memory controllers must be similar in their idiosyncrasies. That said, CPU-NB voltage will likely benefit most from being increased at the outset; 1.325V or +0.1V volts over the stock CPU-NB setting (whichever is least in your case, I do believe seeing somewhere that Thuban IMC voltage was lower by default that that of C3 Phenom). NB voltage will likely need to be brought up to gain stability as well. And it is sometimes said (but not usually by me, so raise this one last, but do at least give it a shot) that a touch more CPU vCORE can help with reaching high overclocks with 4 sticks. But I've always figured that that was more down to the overclock part than the 4 sticks part.

Other settings of interest would be setting COMMAND RATE 2T, (never much seemed to matter for me on Phenom, but that was the rule of thumb with 4 slots populated on s939) trying out the GANGED setting for the DCTs. Increasing DRAM VREF a bit, and if you get to the point where you're throwing everything and the kitchen sink at the thing and still pulling your hair out, a little vDRAM increase won't kill you. Though the problem probably lies on the CPU/IMC end of things, not so much with the DIMMS.

If perchance you do get it to work, taking the time to lower back to stock any voltages which were raised but didn't contribute to system stability would be a nice thing to do.

Also, if you don't already, you really should have the latest MEMTEST86+ burnt to CD or copied onto a USB drive...

Anyway, good luck getting your unsupported 4 sticks@1600Mhz configuration working.