Having boot issues with 'high density' RAM on an otherwise working system

SilverHornet · Jun 12, 2017

Hi,

I've just bought some new RAM for my PC, which matches the specs of the current RAM perfectly. I've tested the new stick solo and with the existing RAM, and it won't even reach POST with the stick in, in any configuration. Corsair seem to think the issue is that it's 'high density' therefore won't work in this board, despite their tool suggesting that stick for this motherboard.

My understanding of high density issues are that if you mix-and-match high and low (or rather, comparatively high to the other stick) it can cause issues, but one stick on its own, shouldn't have any trouble. Is this correct?

This is the ticket I sent to Corsair, with the details of parts and numbers:

I've been having great issues getting my new ram to work; it should be compatible, my old sticks (a kit of bls4g3d1339ds1s00) have seemingly identical specs and timings (999 24) yet the system will fail to boot at all with a stick of the new CMX4GX3M1A1333C9 installed (including just on its own). I'd bought a couple of sticks to install as a pair alongside my existing set, the other packet remains currently unopened.

Is this a settings issue? My motherboard is a M4A88T-V, which is a minor variation on the M4A88TD-M your memory finder tool lists, and that tool does indeed suggest the exact sticks I have issues with.

I also have another computer running a similar motherboard, also using 999 24 1.5v ram, and that has identical problems. I'm reluctant to open the other packet to verify if it's a dead stick, in case it's actually some exotic compatibility issue, as ebuyer may potentially refuse a return on opened packets.

Many thanks for any insights.

brispuss · Jun 15, 2017

With the Corsair module part number CMX4GX3M1A1333C9 used by itself in the computer, the computer doesn't even boot?

Try clearing CMOS.

The Corsair module uses (or should use) relatively low density memory chips. Likewise, the Crucial memory part number bls4g3d1339ds1s00 uses (or should use) the same relatively low density memory chips. However, sometimes different memory chips are used instead on later production runs of memory modules.

What is the ver number printed on the label of the Corsair module part number CMX4GX3M1A1333C9?

What are the number(s)/letters after the "." printed on the label of the Crucial module part number bls4g3d1339ds1s00._____? There should be either four, five, or maybe six characters printed after the period (full stop, or dot).

SilverHornet · Jun 16, 2017

brispuss :

Thanks for assisting, it's greatly appreciated. The computer won't boot with a new stick, no. I've not opened the others to test them but can if needed. When testing the RAM on its own, I used the magic 'memOK' feature on the motherboard, which automatically cycles through a batch of settings, none of which changed anything. I stress the timings and voltage are identical to my current sticks, which is why I chose it. I did also try it in another very similar system, using the same proceedure, and it wouldn't POST.

Corsair version is 3.19 ; Ballistics version is 16FER2. It's also apparently lead free!

I had issues finding information on the density used in these sticks, many thanks again. Where did you find it, for future reference?

brispuss · Jun 16, 2017

Thanks for the details!

Both makes of memory use relatively low density memory chips (256 M x 8), which in this case is = 2Gb (that is two Giga bits), which also equals 256 MB.

Corsair memory chip data is primarily obtained from memory chip details listed at the forum at Corsair website.

Crucial memory chip data is not easily found but is implied by the number of memory chips used (16 in this case; the 16 comes from characters after the "dot"). The Crucial 4 GB modules therefore use 16 memory chips. So, 4 GB ÷ 16 = 256 MB per memory chip. And the memory chip data width is usually 8 bits. The memory chip density = 256 MB x 8 bits = 2 Gb.

The Corsair memory should work in the M4A88T-V motherboard. It is suspected that the Corsair memory is faulty as it doesn't seem to work at all, even in another computer. RMA that Corsair module.

SilverHornet · Jun 16, 2017

brispuss :

Thanks for the resources, that's useful information. A dead stick was my gut feeling too, but with Corsair techsup saying it's a 'high density' issue, I needed a second opinion. Based on that, I opened the other two packets and put them in. It's working flawlessly so far, memtest is at 32% and rising. RMA request has been sent.

When one pass is done on these two, assuming no issues, I'll put my original sticks back in and put the new ones in the second channel. Just as well I had 3 sticks - the odd one out was intended for the other PC (the one I used for verification).

So for future reference, do high density issues ever manifest when testing with a single stick? My understanding is that it can cause problems when one is much higher density than another in the system, but a single stick can never have that issue, for obvious reasons. Is this a correct summary?

Many thanks again.

brispuss · Jun 17, 2017

Keep in mind that although a single module might work OK, it might not work (properly) with any other individual modules (inter-module incompatibility) due to variations in module characteristics (apart from voltage, frequency, memory density, and timings). So there is a possibility of incompatibility between the Crucial and Corsair memory, then again they might all work together nicely. It is a gamble.

The memory controller and (to an extent) BIOS determines what maximum memory density is supported.

As long as modules use memory densities compatible with the memory controller (and BIOS), then they should work fine. Any module using higher density memory chips that are not supported, will not work.

Assuming all memory used has memory density that is less than or equal to that supported by the system, then, in theory, modules with differing memory densities should work. Although there may be slight performance lag due to this difference in memory densities.

SilverHornet · Jun 17, 2017

brispuss :

Well, this is confusing. The memtest run with both sets in ran through two passes overnight, no errors. Windows however halts on booting. This is the case with the new ram paired in any slots. Memtest shows the RAM is fine.

I've not tried the Linux OS yet, that might be fine. I realise this is likely a different problem now so I might be best served making a new thread?

Corsair techsupport are currently refusing to RMA the original dead stick, despite it acting completely differently to the other two (and I said that to them):

This part number is not low density, we do not sell it in low density versions.

This is a high density module and you cannot use these on your system.

This is despite their memory tool explicitly suggesting these sticks for a motherboard that's a very close relative of this one (M4A88TD-M, versus my M4A88T-V). I cannot find anything stating the differences between those boards though.

Further, looking at their forum, 3.1 versions seem to be Micron 256Mx8 ( http://forum.corsair.com/forums/showthread.php?t=68811 ) , so I'm not sure what they consider high density in that case.

I'd appreciate any light you might be able to shine on this?

brispuss · Jun 18, 2017

First, as mentioned previously, individual modules might not work together with each other. But you could try increasing DRAM Voltage by 0.05 V.

If still no joy in getting the modules to work together after raising DRAM Voltage, then try another module (get another individual module). But better still, get a dual channel kit, where the two modules are guaranteed to be compatible with each other.

The terms "Low Density" and "High Density" are relative, and are subjective. There is no "official" standard stating what is and isn't Low Density and High Density memory.

However, Corsair's response that the memory module part number CMX4GX3M1A1333C9 is "High Density" is nonsense (to a degree). First the Corsair module you have is Micron chip based with 256M x 8 bit architecture, which is the equivalent to 2 Gb memory chip density. This is not really considered High Density per se, unless it is compared to lower density memory using 1 Gb memory chips for example.

Regardless, your particular Corsair module is compatible with the motherboard because its supports 2 Gb memory density. But as mentioned in an earlier post, memory manufacturers sometimes change memory chips on modules. So the current generation of CMX4GX3M1A1333C9 modules may be using higher (4 Gb) density memory chips instead of the 2 Gb density memory chips used previously. Therefore the 4 Gb modules will not work because they are not supported by the motherboard.

Quote the version number on the Corsair label (Ver 3.19) to Corsair and that should clarify that is a (relatively) low density memory, probably from an earlier production run. Take a photo of the label as well to prove it, and send a copy to Corsair.

SilverHornet · Jun 20, 2017

brispuss :

For clarity, a restatement of the problem as it stands: the two new modules are fine in memtest - two passes overnight, and same applies with my prior two in the machine as well. However neither windows nor Linux will boot with the two Corsairs in, whether by themselves, or with the other sticks.

I've tried using just the two Corsairs, with voltage raised by 0.0625; nothing changed. Raised it again, Linux hung at a flashing cursor rather than just a black screen; raised it again, Linux bootloop (after GRUB anyway).

So I'm back to auto voltage and my original sticks. Using a SINGLE stick of the new, however, seems to work perfectly, and one stick of new with my current pair. I've never had RAM act like that in a decade and a half of PC building, although I know it's possible. It's either failed memtest or been fine. I suppose I've just been lucky.

I'm wondering if I should just have my original pair and one stick, so 12GB total. Will that cause any issues having one pair working in dual, and one obviously not? When I get the replacement stick from Corsair for the dead one, I'll have two new combinations of sticks to try, so fingers crossed one pairing will work at that point.

For what it's worth the serial number (at least I assume it is) on one stick starts 1701 , the other, 1703. Annoyingly, the dead one starts 1703 as well.

brispuss · Jun 20, 2017

Now I'm a bit confused.

How were the two new (Corsair?) modules tested using Memtest, when the computer will not even boot with either or both modules installed??

The two new modules are both Corsair part number CMX4GX3M1A1333C9? And both modules are ver number 3.19? Please confirm.

Further details will follow after clarification of the above. Thanks.

SilverHornet · Jun 20, 2017

brispuss :

Correct to both. The computer memtests and gets to grub without issue, but hangs when actually trying to boot either OS. It freezes utterly, caps/NumLock won't respond. Voltage raising tests are described above.

I'm not surprised you're confused too, I've never seen ram behave like this.

brispuss · Jun 21, 2017

For maximum performance, memory of same capacity should be installed in each of the dual channels.

Having two 4 GB modules in one channel, and 4 GB in the other channel will lead to a combination of single and dual channel configuration (assuming the modules are compatible with each other). 4 GB of the 8 GB in one channel will operate in dual channel mode with the 4 GB in the other channel. The remaining 4 GB of the 8 GB will operate in single channel mode. This configuration will lead to slight performance limitation because of the single channel mode memory.

Using individual modules is a gamble as to whether they will all work together. Raising DRAM Voltage, and/or raising the memory controller voltage also (particularly when trying to run four memory modules) might help to get the modules to work. But there are no guarantees. It may require trying several other modules as well until an inter-module compatible combination is found.

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