Is Corsair's XMS3 DDR3 PC3-16000 a fake ?

Hi guys,

once it is not usual, but I'm not coming upon this forum for overclocking purpose, at least not now, but instead for a technical advice regarding the corsair's memory I use. I believe an overclocking forum may be the most accurate place to retrieve relevant information on this.

Before I forget about, my main config part are:
Gigabyte P55A-UD4 (rev 2.0) - latest released bios F15
Intel i7-860 (LGA 1156)
Noctua NH-C12P - SE14
Corsair memory (see hereafter).
W7 64bits

I started last year with 2x2Gb XMS3 PC3-16000 memory kit (CMX4GX3M2A2000C9). Hereafter a direct link to the Corsair's technical sheet of this module. http://www.corsair.com/memory-by-product-family/xms-classic/cmx4gx3m2a2000c9.html

At that time I went father for the first time, so I simply setted up the PC with most default bios setting except a few ones regarding RAID config for my storage HDD and some other I don't exactly remember.

Everything seemed fine, RAM running at 2GHz, no reason to be suspicious.

With time going, my daughter letting me some more time I started over again working with the comp. Noticing the ram getting full through my usage, I looked into upgrading with another 2x2Gb XMS3 PC3-16000 memory kit (CMX4GX3M2A2000C9).
Since I couldn't easily find some at my usual retailers or web stores, I finally went for 2x4Gb XMS3 PC3-16000 memory kit (CMX8GX3M2A2000C9). Hereafter a direct link to the Corsair's technical sheet of this module. http://www.corsair.com/memory-by-product-family/xms-classic/cmx8gx3m2a2000c9.html

After experiencing some issues when installing the new modules I managed to have all four banks working together but at 1600 MHz. No way to hit 2GHz as specified. Both kits are said PC3-16000 !!!

Getting worried, I decided to run memtest to insure RAM wasn't damaged. What a surprise:
- the 2x2GB kit is seemingly not PC3-16000 but PC3-10600 instead
- the 2x4GB kit is seemingly not PC3-16000 but PC3-8500 instead

I ran back into windows, and double checked with CPU-Z which gives me the same kind of result. See here: https://plus.google.com/photos/1031...s/5687181750262165633?authkey=CLKnqezjidXLvQE

In the end it's no wonder I have issues trying to run both module together, there are on different base clock, not PC3-16000 at all, none of them !!!!
Simply because they where tested at 2GHz, they sell it as PC3-16000.

May I have your opinion on this before getting toward corsair to ask about this. Is it a common known situation I simply ran into due to lack of knowledge or is it also surprising for you guys. I now have two set of incompatible RAMs except if I downclock them to 1600 MHz. While it's not a major issue itself, I ordered PC3-16000 RAM modules and end up with far cheaper modules.

Try using the XMP option. If that doesn't works, contact Corsair.

Just to be clear, you are currently running 2x2GB and 2x4GB sticks of 2000mhz DDR3 mem on a P55 board? There are a few problems here, first you generally want a common dimm size for maximum performance. Using 4 sticks of memory is alot more strain on the memory controller than 2 sticks. You can try raising the DRAM voltage a bit to help the IMC cope but its possible that you just cant run all 4 sticks at that speed. Do you actually need 12GB of ram? I would drop down to the 2x4GB sticks and run them at 2000mhz.

Thanks for your inputs guys.

@txus -> yup, forgot to say, XMP is activated.

@ssjwizard -> Could you please detail why a common dimm size will improve performance in 4 sticks usage vs 2 ? My board is not quadruple channel but dual-channel. So each paar should be independant as long as in each channel I keep same RAM stick which is the case today.
Also, all four stick work fine together at 1600 MHz. I simply can't have them all working at 2GHz at the same time. Even in tuning the timings and the voltage. Seemed to me it was related to the final state that one paar is PC3-10600 (base clcok being 667 MHz) and the other one is PC3-8500 (base clock being 533).
Since both kits were specified as being PC3-16000 (base clock being 1000MHz) It should have been far more smooth to have them working except if it simply can't due to MOBO limitation. But it doesn't seem so.

Now regarding the 12GB, no you're right, I don't need them. As mentioned I firts looked at finding another paar of 2x2GB but couldn't got one easily. In the end, having 4GB of ram idling around the keyboard don't make me happy, and in the meanwhile I though of setting up a ramdisk (lets 6GB) for e.g. photoshop swap to avoid disk I/O.

Its a farily well known fact that running 4 sticks of memory is alot more stressful on the memory controller. Since the memory controller is only officially rated for 1333mhz its asking alot to run 2000mhz x4 sticks. Since you dont need 12 GB Im sure that if you drop down to the 2x4GB you can run 2000mhz no problem. I know it stinks having nice valuable parts sitting around, but look at it this way you've got backup in the event of a crash, or spare memory for a 2nd rig later, and of course there's always the option of selling them.
Those 2k corsairs are reasonably valuable still you could potentially swap them for a small SSD and that handles your disk caching issue also.

Well, yes you're right, I can keep at spare or I can also keep it running at 1600 MHz as of today.

Still, while I know the board should be able to run 4 sticks (4x4GB GSkill double-sided sticks, same voltage, similar timings, usage was qualified on this board, unfortunately found nothing similar with Corsair's sticks :-() May I ask what kind of settings you would try out to achieve these 4 sticks working at 2GHz before giving up ? If you're interested in giving a hand for a try, I4ll provide all necessary settings I have or hte ones I had with each paar as standalone.

Regarding SSD, well, I follow SSD for a while now but I don't think it's suitable for such a cache/swap usage except for shortening the cells lifes drastically. Also there is no possible comparison in performance between an SSD and a RAM disk (did a benchmark https://plus.google.com/photos/1031...s/5687181750262165633?authkey=CLKnqezjidXLvQE). Even in taking into account the CPU need for the ram disk when using a quad.

Actually my initial concern was to know if its also fairly well known that PC3-16000 sticks are usually not what they're supposed to be but instead PC3-10600 or PC3-8500. I'll head toward corsair trying to have their thoughts while I already guess the answers ;-P

Still thanks for your time guys.

May I ask then, why do you need 12GB? (says the guy with 16GB, damn the memory and it's cheap prices)

Lol, are you serious, I've said it at least 3 times over the past previous posts.

My first choice was to go for 4GB more, I didn't find them, then I chose to go for 8GB more instead (taking care of ordering a ram kit most similar to the former one). WIth these 12GB I was thinking of keeping 6 to 8 GB as ram, and the remaining 4 to 6 GB as ram disk.

Sorry, didn't read that. I usually read posts for the gist.

NP txus.palacios ;-P