Will only boot with 1 stick of DDR2

[mik3ymomo]

Ok so here it the build. It is for a friend and we are using older gear. The memory is suspect but never proven bad.

WD Caviar blue 250GB (New)
Intel QX6700 (taken out of working computer)
Intel 975XBX2 (New off EBay) newest BIOS and all chipset updates driver updates etc
OCZ ZT series PSU 750w (brand new) PSU have also tried another PSU and didn't help
Gskill DDR2 PC2 6400 CL 5-5-5-15 1.8v-2.0v 4x1GB
Windows XP Pro (all updates)
ATI 6770 (proven in another working Rig I have) newest drivers installed
Have also tried Nvidia GT6600 (newest drivers installed)
Thermaltake V3 case (New)
Lynksys wireless Network adapter
LG CD drive Sata (New) have also tried an old IDE disc drive which seems to work as well


Problem is it will only run on 1 single stick of ram. As soon as I add another or all 4 it will either blue screen or boot loop.
I CAN boot into bios and the MOBO is seeing all of the memory and it is showing 5-5-5-15 for the ram timings but it says it is running them at 5-5-5-14. I don't know if that is relevant.

I have tried manually setting the timings and even tried changing them to match the 5-5-5-14 which wouldn't do anything.

I have tried another Intel MOBO (Intel 965 mobo and it's the same story. No difference)

It will boot with any of the memory sticks in any of the slots, just not more then 1 at a time.

I tried to make a memtest USB Jump drive to boot from but it won't even boot from a USB or Disk drive with all of the ram on the MOBO.

I have done a few clean installs on the HD in case it got fouled up and corrupted a driver. No better.

I am at a loss. Nothing is showing up in the logs. As soon as I take out the extra sticks it will boot and run normally.

The CPU temps all look under 49C at all times. No idea what could be the problem. ESP since all the ram will work individually.

[Tradesman]

You can try with manual settings, with the multiple sticks it may want the full 2.0 volts so will have to input that manually...and mobo specs say only support up to 1.8 volts

[mik3ymomo]

You can try with manual settings, with the multiple sticks it may want the full 2.0 volts so will have to input that manually...and mobo specs say only support up to 1.8 volts

Thank you for the Reply,
I have not seen any way in the Bios to change the voltages of the Ram. Only the timings

[Tradesman]

That may it then if the mobo has DRAM voltage locked at 1.8 volts, then you might try 667 at 4-4-4-12, may be able to run multiple sticks then at 1.8

[mik3ymomo]

That's good info, now I know what to try next.
Thank you

[Tradesman]

Not a problem, let me know if it works

[mik3ymomo]

Solved

I did some research on the Intel 975XBX2 Mobo and apparently it has a "Watchdog" feature that keeps certain Bios settings hidden. To disable the Watchdog you must move the jumper on the Pins. (Do not remove the Jumper) just move it onto the other 2 out of the 3 pins.
Turn the computer on and boot into the Bios.

Now you can disable the "Watchdog". Move it from "Enable" to "Disable" Exit saving your changes.
Now shut down the computer and replace the Jumper back to the original pins and reboot into Bios. Now you can change the frequency of the memory etc. Previously you could only adjust some of the features like timings via the manual settings. You can now OC the CPU and other features not shown previously.

I know this gear is old and from what I understand the "Watchdog" feature is not on the newer i3, i5 and i7 Architectures.

My Solution was to drop the frequency down from 800mhz to 667mhz or 533mhz. I cant remember which one. But it was whatever the next selection available in the drop down in Bios for the memory frequency.

I was not able to change the voltage to the Bus per se but "Tradesman" pretty much hit the nail on the head with the voltage being the problem. I think lowering the frequency in effect changed the voltage or current being drawn or the needs of the memory from the bus enough to stabilize it running all four sticks.

Thanks Tradesman!

[Tradesman]

Lowering the freq cuts the amount of voltage needed, glad it worked out, and nice troubleshooting on the Watchdog, That's something I'll have to file away, Thanks!