Gskill Memory compatibility

[eshaki]

Hi,
I have memory compatability problem that I would be thankful if you can help me with.
I'm using gigabyte GA-P55A-UD5 motherboard with 2 x 2 GB MEMORY CHIPS MODEL: F3-12800CL-7D-4GBRH DDR3-1600 CL7-7-7 1.6V (total memory was 4 GB).
Recently, I've added another 4 GB memory with two GSKILL chips model: F3-12800CL7-4GBXM DDR3-1600 PC3 12800 2GBx2 XMP CL7-8-7 1.5V.
The two models of chips are the same speed and spec (except the CL). I was using them for short period of time with no problems, but recently I've been getting the following error:
Every time I'm using ALL of the memory (4 chips of 2GB each in each of the 4 memory slots of the motherboard) the computer is crushing without any notice (like doing reset).
From the windows event viewer I got eventid 41 without any other details.
From search in Microsoft knowledge base it seems that it is caused by one of the following errors:
1. Overclocking
2. Memory problems
3. PSU
4. Overheating
I've cancelled out all of the other possible cause of crush except memory problems (according to all monitoring tools & bios definitions). I've also updated all the hardware drivers (including bios) in order to cancel any other hardware issue.
The Problem was not solved.
WHEN I'M PULLING OUT 1 CHIP OF MEMORY THE COMPUTER IS WORKING WITH 6GB ABSOLUTLY FINE!!! (The same with less memory) AND IT DOES NOT MATTER WHICH MEMORY CHIP I'M PULLING (either from the first or second model) and from which slot (the computer indicate 6 GB of usable memory Not 4).
The bottom line is that the memory chips seems to be compatible (both with the pc and with each other) but I cannot work when I'm using ALL OF THEM TOGETHER (I have also done memory test on each of them ? didn't have any error).


MY QUESTION:
Are the two memory chips are fully compatible? And what can I do in order to be able to work with all of my memory? (both of the memory chips are under warranty)

[Tradesman]

Any time you mix sets it can be problematic, which is why it's always best to get get a single set of the full amount of DRAM you want/need (also, with a single set you can use XMP). In your case, I believe it may be a simple timings/voltage problem. I would make sure you have the latest BIOS, then try disabling XMP if it's enabled, set the DRAM to Auto or Manual, then manually load your base timings, ensure CR (Command Rate is 2T or 2N), raise DRAM voltage to about 1.57 and try that, if no joy, try raising the MC (Memory Controller) voltage about + 0.06)

[eshaki]

Thanks for the response. I've tried all the suggestions you've made - with no success.
After rethinking about this - I did found something that would suggest it is more a chip problem then a timing/voltage problem.
I'm currently working with 6 GB of physical memory (two 2 GB chips from the first kind and one from the second). If the route of the problem was in timing/voltage - Why doesn't it happens now? (The computer is totally stable). Only when working with 4 chips of memory (two from first kind and 2 from the second) the problem occur. I'm starting to think the problem is with one of the chips (altough in memory check there is nothing wrong). AM I CORRECT? what do think?

[Tradesman]

It may be the system isn't isn't setting the advanced timings correctly for four sticks, if you can post your advanced/secondary timings will take a look and see if anything looks out of whack

[eshaki]

and can i do that? from the bios?

[Tradesman]

Yes, check under the DRAM settings, should be one to show secondary or advanced timings