DFI LT-X48-T2R + QX6850 Bios Loop Nightmare-Please Help!!

[CyborgGreenAW]

Hi Everyone,

Please can someone with greater knowledge look into these issues for me as its driving me totally nuts!!

The Problem:
QX6850 + DFI X48-T2R will not post more than once. Gets trapped into a loop. What happens is 1st time it posts and you can go into the bios then whatever you do on the settings or not do anything just saving it as is on defaults the system will no longer post and just powers on for less than 1 second before powering down again and then goes into a loop of power on/off for 1 second until you turn the mains off so no way to read the LED error code as it does not stay on long enough!!
Only way to get it back on is to reset & clear CMOS and all the jumpers to wipe it back to default. The system will work perfectly if you do not go into the bios & just let it boot but I need to enter the bios to change settings otherwise the HD boot order is messed up (along with several other bits of hardware). I am not overclocking anything at all either just talking about using the default timings on everything and both CPU's are FSB1333 by default and all my Ram is DDR2-667.

Things I Have Tried:
1: Using another CPU. I have a Q9450 which I am now selling (this was the original CPU I put into this mobo when I bought in new in Aug 08 and it worked perfectly and still does). So say after the bios loop with QX6850 if I clear CMOS etc etc then use the Q9450 the system works perfectly and you can change anything in the bios or create different profiles and it is totally stable and perfect.

2: Using the QX6850 in an old P35 Asus motherboard. Put the QX6850 back into the P35 board I was using it in before and it works perfectly with no issues.

So as you can see I have eliminated the CPUs as being the issue.


3: Using different Ram. I Have 6 different Ram sticks and all of these in whatever combination or just using 1 stick all work fine with the Q9450 + X48.
None work with the QX6850 in the X48.
All sticks work with the QX6850 in the P35.

So as you can see the Ram is not faulty at all.


4: Changing X48 jumpers to force the CPU to FSB1333 or leaving those jumpers as default for CPU to select FSB. Neither makes any difference whatsoever.

Ok so as you can tell I have eliminated the CPUs, Ram & motherboard as all work just cannot get the QX6850 + X48 combination to play nice even though both are designed and supported according to Intel & DFI.

I can go into the bios with the QX6850 + X48 once before it loops but am I missing something really simple here? What on earth do I need to change in the bios to get these parts to work properly?


Please can someone point me in the right direction as I spent around 7 hours yesterday trying to fix this but have now come to a dead end and have no more ideas left to try.

[Clunk]

Welcome to the forums

There are a few things you can try. Please add your full system specs to your profile for us.

If you have any optical devices, leave them unplugged while testing.

We need to know what the post code LED is saying when it goes into this loop. I'm wondering if the CMOS battery is faulty - these are easy to find and are pretty cheap, so might be worth trying one of these as a precaution.

You may have a corrupted CMOS, in which case, you will need to do a long CMOS clear - Flip the battery out (new one if possible), unplug the PSU, remove RAM, give the power switch a couple of presses to discharge any current....leave it for a couple of hours or more if you can.

Put one stick of ram back in and try again.

Let us know how this goes.

P.S. I see that you have 667MHz memory, you won't get very far overclocking with that I'm afraid.

[Kelainefes]

Hey there, welcome to the forums.
Sorry about your PC troubles, you should enter your complete system specs in User CP>Extra Options>System Specs, so we can help you.
What BIOS are you using?

EDIT: Damn monkey face beat me. It's my turn at eating my hat.

[CyborgGreenAW]

Originally Posted by Clunk

Welcome to the forums

There are a few things you can try. Please add your full system specs to your profile for us.

If you have any optical devices, leave them unplugged while testing.

We need to know what the post code LED is saying when it goes into this loop. I'm wondering if the CMOS battery is faulty - these are easy to find and are pretty cheap, so might be worth trying one of these as a precaution.

You may have a corrupted CMOS, in which case, you will need to do a long CMOS clear - Flip the battery out (new one if possible), unplug the PSU, remove RAM, give the power switch a couple of presses to discharge any current....leave it for a couple of hours or more if you can.

Put one stick of ram back in and try again.

Let us know how this goes.

P.S. I see that you have 667MHz memory, you won't get very far overclocking with that I'm afraid.

Thanks for responding. Have added my full system spec to the profile. I cannot tell you the post code LED as the mobo powers off before it appears then powers straight back on again in the loop its trapped in so no way to read this I'm affraid. I have already replaced the battery for a new one. Also I tried to get it to work with no optical drives or hard drives plugged in and 1 stick of ram but still the same problem it goes into the loop after the first bios post whenever I enter the bios and exit and save.

Could the CMOS really be corrupted if the exact same motherboard & system parts work perfectly with the Q9450 and works ok with the QX6850 until I enter the bios and save the initial setting to CMOS??

[Clunk]

What BIOS version are you using?

[CyborgGreenAW]

Originally Posted by Clunk

What BIOS version are you using?

Initial release only as it said it supports the QX6850.

[Kelainefes]

try to update anyway to the latest stable, as i don't think thay dropped support.
You still got the Q9450 to reflash it to the original BIOS if it goes belly up with the QX6850 right?

[CyborgGreenAW]

Close to giving up on this now. So frustrating. Wondering if its simply that DFI did not test the QX6850 with this Motherboard at all as it simply refuses to work once you enter the bios once and save to CMOS. Yet even if I do not clear CMOS or do anything else but swap the Q9450 back in it works perfectly straight away. Even flashed the Bios today to the 02/10/08 version and it made no difference whatsoever.

[Clunk]

I'm out of ideas mate, I can ask DFI for you, but it won't be until sunday night - please remind me on sunday night and I'll see if they have any idea what the problem is.

[Kelainefes]

Yeah now that the BIOS has been flashed only thing that comes to my mind is that the CMOS or something related to it is somewhat damaged. But even his does not make sense as the Q9450 works ok.
I hope some guy at DFI can help you or tha they will take care of the problem for you in any way.