2x F3-2400C10Q-16GZH won't run at 2400MHz (X.M.P.)

DieHertz

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Oct 27, 2014
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Hello everyone!
I have just purchased quad-channel kits for my computer (was using triple-channel for some time), and there seems to be some problem.
My configuration:
Rampage IV Black Edition (firmware version 601, then 801)
i7-4820k
2x F3-2400C10Q-16GZH amounting to 32GB in total

All settings are at factory-defaults and no overclock attempts were made so far.
After putting both kits into the motherboard and switching Ai Overclock Tuner to X.M.P. (tried both profile 1 and profile 2) I've navigated directly to memtest86+ and encountered many errors coming from module located in D2 slot. I've tried to swap C2 and D2 (which is difficult by itself since I'm using Noctua DH-14, forcing me to dismount it before manipulating DIMM slots) to see some effect, resulting in some unpredictable change in errors patterns: d2 was still failling (although on different addresses), so was b1.

I was counting on the memory working at rated speeds without too much effort, and I'm not particularly experienced in overclocking, therefore at the moment I can't even determine if the problem is with faulty memory or weak CPU's IMC (is that even possible that 4820k can't handle 8 sticks at 2400?). I've decided decreasing frequency down to 2133 and tigthening up some timings (currently at 9-11-10-29) while still using the X.M.P. profile for all other settings, which runs just fine and handled to run memtest86+ for 3 hours.
 
Solution
You should be fine with that, only other options would be upping the volts on the ram but I am guessing you already were at 1.65volts which is max for the board/CPU according to the manual.

DieHertz

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Oct 27, 2014
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The list available online (RIVBE manual) assures that even F3-19200CL10Q2-64GBZHD should be working fine, which is 8x8GB :)
I've felt like I should be getting 4x8, but they're not easily available in my country.
Thanks, I should stick to 2133 then, fortunately it seems to work just fine.

P.S. Diving through ROG forums now I see many cautions against combining even identical kits (like I did with 2x 4x4GB), getting single kit of desired density instead.
 

DieHertz

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Oct 27, 2014
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Seems like some problem still exists, I experience mysterious unexpected reboots of Windows every once in a while (usually not often than once a week).
Memtest86 outputs are clean so far, but I've already seen the same DIMM modules spamming errors from memtest, so I guess I'll have to RMA my kits, or at least one of them (but how am I going to find which one after all the slot swapping? :) ) :-(