PC plays up with 16gb ram? fine with 8gb

_Jimlad_

_Jimlad_

_Jimlad_

Soldato
Joined
5 Jun 2005
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Southampton
yes yes yes, i know 16gb is not needed at all....

anyway my pc will run and work like a dream stable as anything with 8gb (2 x 4) however when i add the 2nd set of 8gb it will work on and off with all sorts of strange errors, crashes, blue screens and odd happening.

i have tested each and every stick with mem test and all combinations work fine, its just having 16gb that throws the pc.... Any ideas?

Corsair 650D Case
Corsair TX 650w V2 PSU
Asrock Z68 Extreme4 Gen3 Intel Z68
Intel 2600k i7 @ 4.4ghz
Corsair H60 CPU Cooler
Corsair XMS3 16GB DDR3 PC3-12800C9 1600MHz ( 4 x 4GB)
Crucial RealSSD M4 128GB
Gigabyte GeForce GTX 670 Windforce 3X 2048MB GDDR5 PCI-Express
2 x 1TB Weston Digital
Benq XL2420T 24" TRUE 120Hz 3D Vision 2.0 Widescreen LED Monitor
Windows 7 Pro - 64 Bit
 
The voltage you need to adjust primarily is the one linked to the memory controller often called VTT. On ASUS boards which I use extensively its known as VCCIO.

Adjust this and the CPU core voltage slightly and you should be able to get it stable.

1.65v is fine dont worry. Just dont go much over for 24/7. When I bench I put 1.825v through my dimms to run high mhz cas6 on SB and every single CPU has been fine and I do a lot of benching. I would not be worried by 1.65 at all.
 
The info in the above link just states intels stance, not how or why. Also theres been really no evidence that 1.65v memory degrades anything and i've got many builds out in the wild that don't skip a beat with 1.65v for well over a year now.
 
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The memory controller is in the die of the cpu thus they are linked, rather complicated and i do not know the ins and outs but yes, the RAM voltage can affect the cpu. With Nehalem it was recommended to keep the difference between RAM voltage and the VTT no more than 0.5v and preferably under, so for example at 1.35v VTT and 1.65v RAM the difference was 0.3v, thus safe, at say 1.9v it'd be 0.55v thus unsafe.

I do not know if this still holds true for SB chips, could very well be as the avg VTT is 1.05v, making 1.55v 0.5v difference and 1.575 just over at 0.525v, could just be a coincidence! , however since most of us use more VTT usually when overclocking this difference would still be more or less safe at 1.6-1.65v, this is assuming that the 0.5 (or maybe its more or less now) difference still holds true, i do not know for certain as some have said yes whilst some have said it dosen't matter.
 
Could try running the RAM at 2T rather than 1T as that can make it more stable when all slots filled, however I'm speaking from experience of older platforms so don't know if this still applies with SB chipsets.
 
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