Problem with booting new homebuilt system

I recently put together a machine using an Intel i7-920 CPU, 12GB of CORSAIR TR3X6G1600C8 DDR3 1600 Triple Channel RAM and a GIGABYTE GA-EX58-UD5 X58 RTL motherboard with a Corsair 1000w modular power supply. Everything went without a hitch and is currently running Windows 7 RTM 64 bit edition wonderfully.

So, I decided to build a new computer for my son as well, but I didn't want to outlay cash for another i7 CPU and 1366 motherboard. Therefore, for my son, I chose an INTEL CORE I5 750 2.66G , 4 GB of 2Gx2 MUSHKIN Dual Channel 996659 RAM and a GIGABYTE GA-P55M-UD4 P55 motherboard (for 1156 socket) along with a 650w power supply I already had. However, unlike the previous system that I built a few weeks ago, this one is having problems. It won't even POST.

When I apply the power, the computer briefly begins to power up (lights on, fans running) and then within a second or so, it powers down and then about five seconds later repeats this cycle. This self-induced power cycling goes on indefinitely. I am at a loss to determine what the problem is.

I've heard that some people with this Gigabyte mobo experienced this issue and it was their RAM that wasn't compatible, even though one person indicated that he used RAM from the compatibility list on Gigabyte's web site.

The Mushkin RAM I tried is part# 996659 and I saw that Gigabyte has the Mushkin 995659 on it's compatibility list, so a slight difference in numbering, but it's basically the same parameters (2 x 2GB, 1600, DDR3). So, just to see what would happen, I removed those two modules and installed two of the Corsair TR3X6G1600C8 memory modules from my previously successfully built computer's Gigabyte mobo but again, I experienced this self-induced power cycling.

If anyone has any suggestions as to what might be the issue at hand, I would GREATLY appreciate it! I don't want to start returning items until I know what the problem likely will be.

Thanks in advance!
4 answers Last reply Best Answer
More about problem booting homebuilt system
  1. Best answer
    Does the 650W PSU you have use a 4 or 8 pin ATX connector for the CPU? If it is a 4 pin, maybe it is in the wrong ones.... just a thought.
  2. The "READ before posting about boot problems!" sticky at the top of the forum was created to troubleshoot this exact problem. I would go through the entire checklist.

    Make sure to try each stick of RAM by itself in the first RAM slot. Check the motherboard owners manual to ensure you're using the correct RAM slot. It would also be a good idea to perform the breadboarding suggestion in the checklist to rule out a short.
  3. To all that have responded. Thanks for your assistance! I did in fact find the cause of the problem and it was a "Doh!" moment on my part. I didn't have both 12v ATX connectors attached to the motherboard. Once that was hooked up, everything is beautiful.

    Sorry to have bothered you all with a silly mistake on my part. However, maybe someone else will see this thread and avoid my mistakes.

    Thanks again everyone!
  4. Haha, it happens to us all. Sometimes it just takes someone else to run it past.
Ask a new question

Read More