Cold boot fail with 2 DIMMS installed


I have a setup which consistently fails to POST when cold, but ONLY when 2 DIMMS are inserted. There are dozens of 'cold boot' issues throughout this and other forums but I've tried everything they suggest based on the equipment I have available and I'm getting no-where.

My PC will boot ok with 1 DIMM (2gb) in either Slot 1 or Slot 2.
Insert a second 2gb DIMM (Slot 1 & 2 or 1 & 3 for dual channel) and I get nothing on first cold boot. Fans come on & case lights indicate all typical power, limited drive activity, no keyboard lights. Long beep sounds.
Wait a little longer and we might get keyboard lights so I suspect we're 'heating up'. Probably 3-4 mins of power in total and I get a POST on further resets.

I've reflashed the BIOS and basically kept all settings to auto or standard. I've tried both DIMMS themselves and performed memory tests on both POST and Windows 7 boot test and nothing is showing up. As far as I can tell, the DIMMS are paired (CPU-Z confirms identical specs).

Someone's mentioned the power supply might be a problem. I've tried increasing the voltage to the memory but this won't help any current issues. Doesn't seem to work anyway. Bad capacitors could be a reason but the board has solid state Japanese caps and I cannot see any obvious problem components. Since reflashing the BIOS I've not managed to get dual channel boot at all. I've no idea whether I need to set the BIOS for dual support.

My system is for internet streaming and watching films...not interested in gaming or any stress applications so it's pretty basic. I'd would prefer to have 4gb in use though and run Win7 64bit if I could.

System: -

Asus P5N-D
Transcend 2gb x 2 PC6400
ASUS HD5450 PCI-E card
Seagate SATA drive

Any help from members would be appreciated

Many thanks.
4 answers Last reply
More about cold boot fail dimms installed
  1. Have you tried running Memtest86 on the RAM? OR are you just using the self-test on boot? Yes, it could be a powersupply issue, but it could be several things. It could even be a motherboard problem. I'm leaning toward the latter.

    Lets run a test on the RAM and go from there. Memtest86 is a free download, you will create a boot image disk with it and run it. Run it with both RAM sticks, and with one at a time. I'd let it run for a couple hours. It will make several "passes" on the RAM and may pick up something on another pass that it didn't in a previous.

    I would advise leaving the voltages at their factory recommended specifications. The system should boot at the correct settings, turning up the juice is not something I'd do for diagnostic purposes. Simply because the system SHOULD work at said factory recommended settings.

    The RAM technically doesn't need to be "paired", thats a Rambus thing primarily. We're working with DDR2.
  2. Thanks for the quick response and advice nekulturny.

    I've ran the memtest you suggested for several hours last night with each stick and both together and there was no errors reported. Interestingly since the computer was on so long I was able to boot with 2 sticks in either single or dual channel config without any problems. However, let the machine cool a little (10 mins max) and we were back to square one. But because there was still some warmth i was able to get to a working temperature relatively quickly. Still awkward though.

    Note that the 'working' temp is achieved much quicker with 2 sticks in single channel than it is in dual channel.
    I also switched to a 550w PSU from the 450w i was using previously. Didn't solve the problem, but what i do note is that it takes longer for the boot sequence to 'make up it's mind' not to boot. In effect, lower wattage PSU and basically the PC knows it's no chance of starting so lets me know sooner. i hope this makes sense but to be fair, I only witnessed this on a couple of attempts so could be a fluke.

    Can't believe adding one extra stick drives such a demand on power. Do you think if I boosted the voltage to the board (not sure which output would be best), we might get a solution ?. Or maybe if I switched to a 600w PSU or higher.

    Thanks again.
  3. I honestly dunno then, thats really strange.

    And no, a 2nd RAM stick is not going to be an increased power draw of any real consequence. I don't see how it could even dream of being a "make or break" situation as far as the PSU wattage is concerned.

    A 550 watt power supply, even a 450 watt is more than that system should need to operate properly. I ran a power supply calculation on it (, I got 218 watts recommended. So your power is adequate.

    I'm thinkin the the motherboard is hinky. Sorry I can't give you much in the way of certainty. But thats where I'm leaning.
  4. Thanks again for the quick response and for doing that PSu check.

    I tend to agree with you. I'm just going to run it with one stick on a 32bit OS and I'm sure it'll be fine.

    Your time and help was much appreciated.

Ask a new question

Read More

Homebuilt Systems