GA-870A-UD3 wont POST until CPU reseat

[instagibb]

Hey all I'm having some issues with my system. See below for details

Specifications:
-----------------
CPU: AMD Phenom II 955BE (Stock cooler)
MOBO: Gigabyte GA-870A-UD3 (Rev 2.0)
RAM: G.Skill Ripjaws F3-10666CL7D-4GBRH (2x2GB) DDR3
GFX: Gigabyte ATI Radeon 5850
PS: Zalman 600 Watt

Configuration:
-----------------
DDR (1333Mhz)
Memory Slots 1&2
Unganged
7-7-7-21 as per memory rating (manual setup) for some reason the SPD ratings are way of the supposed rating of the RAM

Everything else is at defaults

Background:
---------------
I built this machine in Oct/Nov 2010 and at first all seemed fine. There were no problems and seemed to run perfectly
after around a month things started to play up. My system started hanging like just full hang (with repeating sound garbled graphics etc)

The problem:
---------------
After booting and using the system for some arbitrary amount of time it hangs (or reboots/BSODs) and will not post with memory in slots
1 or 3 until I reseat the CPU (Bizarre). Funnily enough after doing this the system will seem to operate flawlessly until I turn it off
for the night and come back the next day and have to repeat the process. So the cycle is something like this:

Turn on PC after arriving home from work
Wait till it hangs
Power down
Reseat CPU
Power up
Use it all night with no issues
Power off for the night
Repeat

Things I have tried:
-----------------------
Single stick of RAM in slot 2 or 4 appears to be stable but I need my 4gb
Relax RAM Mhz and Timings - No change
Memtest86+ tests the RAM out fine (over 50 passes each)
Different GFX
Different Power Supply

Crazy observations:
------------------------
Sometimes the memory is detected at DDR400 in Memtest86+?? even though the BIOS and POST screen say DDR1333 (666 etc)

Help Me!?
------------
I am finally in a position to get some new parts to test with but I dont know what to start with? to me it seems like a faulty CPU (memory controller perhaps?) or is it a motherboard issue or even an incompatibility with CL7 memory?. If anyone can offer any insight or perhaps suggest some things to try I would be most grateful. Ive never had a system so temperamental before.

If you read this whole post... thank you

[Dark Mantis]

Hi and welcome to the Gigabyte Forum.

Even though you haven't been overclocking your memory I supsect this crazy problem has something to do with the CPU's weakness of it's memory controller. My advice would be to RMA the processor.

I expect absic will be able to either confirm or deny that this is indeed the case shortly.

[absic]

Hi there,

Whilst it could be a problem with the CPU I have to say that at this stage I would think it unlikely and I personally, would be looking at other possible causes.

What version of BIOS are you running? If it is not the latest version (F5A) then the first thing I would do is update to it.
You can download it from here: http://www.gigabyte.com/products/product-page.aspx?pid=3423&dl=1# Use QFlash to update the BIOS and I would suggest that you disable the Keep DMI Data Option before you actually flash the BIOS. If you are not sure how to use QFlash check here: http://forum.giga-byte.co.uk/index.php/topic,2441.0.html

[jolphil]

Sometimes the memory is detected at DDR400 in Memtest86+?? even though the BIOS and POST screen say DDR1333 (666 etc)

I have the same board as you but with different memory modules(mushkin 2x4gb), and Memtest 86 4.1 does indeed show it at  400 when a single stick was tested..However when both my sticks (unganged mode in slots 1&2) were tested the memory showed 1333..
It may be just a memtest hiccup..  
jolphil


MB version 2.0 BIOS F4

[instagibb]

Hey thanks for the replies...

BIOS: F4 (I didn't go to F5a as it is still BETA?) Should I still update?

Ive noticed as well that the SPD detection in the BIOS is way of the advertised timings... is this normal? RAM is 7-7-7-21 and the SPD in the BIOS is something like 9-9-9-24? Also in the BIOS "sometimes" the SPD column and the AUTO column differ in readings.

Also I forgot to add this in the initial post but sometimes after the lockup/hang/reboot/BSOD what have you. The machine will POST  after a while (which is very very rarely) and give the warning about overclocking. The thing is I am not over clocking at all. I have no interest in doing so and as such make sure my BIOS is setup correctly. I thought it may be an issue with the Cool and Quiet adjusting clock speed and voltage so maybe the F5A will help.

Also these lockups dont just happen in windows... sometimes the machine will just hang in the BIOS screen or on windows startup etc. Often the machine just resets to a blank screen and sounds like its continuously rebooting but there is no POST beep or output to the screen. This is when i have to unplug it and reseat the CPU to get it to POST again

The most annoying thing about this is that after the CPU re-seat the system appears to be stable for the rest of the time I am using it.

@jolphil - I will ignore the DDR400 thing then... it was just a random event but I thought id mention it.

Sorry if this information is incoherent or rambling. Im just trying to give as much detail and I am putting my thoughts/observations down as I remember them

[absic]

Although the latest BIOS is a Beta version, they are usually pretty solid and are quite safe to use and in your particular situation I would recommend that you update to it.

Yes, the default settings for memory timings are as you stated and you would have to manually set them to those specified for the RAM Modules.

[instagibb]

Thanks for your advice so far,

Well last night I updated to F5A using QFlash. I have not had the time to test it yet but I will keep you up to date as I use it tonight

Any other suggestions that may help me to confirm faulty parts would be most appreciated.

[instagibb]

Ok so today there is no change. The F5A BIOS has made no difference and the problem still persists

So where to from here? CPU? MOBO? RAM?

[absic]

Hi there,

I think I would probably go with RMA'ing the motherboard as what is happening doesn't seem right.

Of course, if you bought all of the components from the same place, you could RMA the whole lot and get them all checked out as troubleshooting this kind of issue can be a real pain if you don't have the correct equipment or spare parts to swap things out.

[dadda]

hi.
i've got the exact same problem with the same MB.
has anyone found a solution by now?