GA-EX58-UD5 & 12GB of RAM

[tchuyev]

Hi,

I'm having weird behaviours with my Gigabyte GA-EX58-UD5: it's loaded with 12GB RAM of G.Skill F3-16000CL9T-6GBTD
DDR3-2000, certified for CL9-9-9-24 & 1.65v

1./ When the computer is 'cold', the full amount of memory is NOT recognised properly on startup: it varies between 6, 8 or 10GB of RAM
After a few minutes and a hard reboot everthing is fine (memtest is also OK after several passes), hum...
Have you ever encountered this or do you have any explanations?

2./ I just can't set the performance to 1600 or 2000Mhz as it is supposed to run on paper!
The only viable and reliable option is 1066Mhz, no more...
That's a bit of a waste as the memory modules are certified to operate at a higher latency
Any ideas?

I've been using several BIOS from F5 to F9e without success
Cheers VERY much

[MindLESS]

There's some technicaly incorrect information in what you posted.

The latency is the CL (short for column address strobe latenct or CAS latency) - lower latency is good.
The MHz is the speed the memory runs at, where bigger is better.

Most motherboards I know of more sticks usually means running lower performance (lower speed, higher latency) to increase compatability.
I can't comment on your setup as I don't have any experience with the X58 chipsets. It is possible to have faulty memory (there is another post about someone having problems in the P55 forum and swapping RAM fixed it) - have you tried running the memory in a 6GB config and seeing if all of the modules will run at a higher speeds / lower latency before trying them all together?

[bge]

There is a limitation of Intel X58 chip with 2 DIMMs per channel.

X58 allows higher frequencies with 1 DIMM per channel (for example 3x2.0Gb) and sticks with 1066 MHz with 2 DIMMS per channels (6x2.0G).
This limitation is clearly specified in the Gigabyte Memory Support List

http://www.gigabyte.com.tw/FileList/MemorySupport/motherboard_memory_ga-ex58-ud5.pdf

Other motherboard brands, such as Asus, have the same limitation of course.

[bge]

In the other hand I just saw this post in the overclockin section of this forum:

http://forum.giga-byte.co.uk/index.php/topic,207.30.html

It seems that a user was able to get a stable overclocked system with 6 DIMMs. 

[jonj678]

I know a chap running 12gb at 4.3ghz cpu clock, the ram is around 1600mhz. He was fortunate to get a processor with a good imc, and happens to know what he's doing as well.

I believe I'm right in saying that noone, anywhere in the world, is running 12gb of ddr3 at 2000mhz. Unsure what made you think you'd be able to, the ram is rated up to this speed but the processor definitely isn't. Anything over 1066mhz is overclocking in the eyes of Intel. If you drop to 6gb you will probabl get the ram up to 2ghz but even then you might not.

You are quite correct in saying that you wasted your money buying 12gb of 2000mhz ram. I'm surprised noone told you this. With time and persistence you will probably get 1600mhz cl8 at 4ghz cpu out of the system.

No change of motherboard will resolve this. Changing cpu repeatedly will eventually get you one with a stronger imc through blind luck, though this one also won't run 12gb at 2ghz.

p.s. a lot of people can't get 12gb at 1600mhz stable either, Corsairs support forums recommend running at 1333mhz.