I built a new PC last December, 4 months ago. Right from the start it had problems with crashes.

It looks like I may have finally solved the problem but the solution was not what I expected.

This experience has turned out to be another example of the power of marketing to distort reality and how data helps you find the truth.

recap

I built a new PC. I tried Vista with Fallout3 and I had all kinds of crashes. I switched to XP and had fewer crashes. Conclusion: Vista was a problem.

Over the past 4 months, I have continued to have crashing problems even with XP. Some nights I could game without problems; other days I could barely keep the thing running. Conclusion: My PC hardware was a problem.

My crashes had several symptoms:

• Sometimes it wou• ld reboot itself.
• Sometimes the screen would go black and the fans would turn off but the lights were still on.
• Sometimes it would lock up.

The fix in all cases was to cycle the power and reboot. What could be wrong?

finding the root cause

Since I dont have any special tools like an oscilloscope or the skills to use one, I generally use trial and error in this situation.

It could be a bad video card, bad memory sticks, bad motherboard, bad power supply.

Since my system worked most of the time I knew it wasnt a total failure. Heat is the main cause of intermittent failures so I checked that using HWMonitor and my fingers. My system has good fans, good airflow and it was clearly not getting hot.

I ran memtest on my system. Never any failures.

PSU mysteries

The only thing left was a power supply. My Seasonic S12-550 must be the problem. But is it not big enough or is it providing uneven power?

I embarked on 2 weeks of internet research. Damn! I spent a lot of time on this. I did learn a lot about power supplies, "rails", and the importance of current draw over wattage, the most common marketing term. However actual data of power usage is amazing hard to find. It is out there but inconsistent.

To test the idea of not enough power, I removed extra items to see if it helped. I removed my 2nd hard drive and my sound card. My system seemed to crash less but it was just a feeling.

My previous PSU was a Seasonic S12-430 and I never had problems with it. I chose Seasonic in the first place because they are known as top quality and the quietest PSU's out there. I found one internet user who had similar symptoms as me and he felt the cause was a faulty Seasonic PSU.

After much soul searching about spending more money on this "game" PC, I decided to try a different brand and go up to 650W.

The first funny thing is that while there are a lot of companies that sell PSU's, there are only a few that make PSU's. Corsair and Zalman are both made by Seasonic. OCZ bought PC Power and Cooling who makes theirs. So while I might get a different brand I probably wasnt getting a different PSU.

Based on reviews, I eventually narrowed it down to a Corsair modular supply with a 5 year warranty. But what size? 520W or 620W? The prices go up very quickly.

If you look at PSU's and the test systems used in reviews you will find that most of them use 750W or more. They sell 1,500W supplies now!! These big PSU's are all aimed at enthusiasts who want to use top video cards and dual-video cards. In other words, that is kind of me...

I agonized about this and eventually ordered another set of memory sticks (just to be sure) and the Corsair HX520W.

data shines light

While I was waiting for my new stuff to arrive, I found my Kill-A-Watt meter. This is a little device that tells you how much current (amps) and watts you are using. So I plugged it in and found...

My system never used more than 200 Watts or 1.8 amps.

Are you kidding?!? After all that research and looking at how large the PSU's for sale were, actual results show that I could have kept using my 350W PSU from 3 years ago?! Wow. There was a huge disconnect between my actual needs and my impression of my needs based on stuff I read/heard. In other words, marketing convinced me to over-purchase.

Clearly the problem was not that my system lacked power. Moreover, PSU's are design to be most efficient at 65% of capacity so my 550W PSU should be pushing a 350W system -- not a 200W one.

But the problem could still be a defective, unstable PSU or the memory sticks.

human error

I put in the new memory sticks and guess what I found? I found that I had connected my video card to the PSU incorrectly.

Modern video cards for gaming require their own power connection. The connectors are called PCI-E and my PSU had several cables for this - 4-pin, 6-pin and 8-pin.

In December, I put the video card into the case and connected a 4-pin cable to my video card and off I went.

This time I noticed that the video card actually had a 6-pin connector. Ooops. The wrong connector meant the wrong power to the video card which would probably cause a hardware problem under certain load conditions, ie the exact thing I was seeing.

After putting in the new memory, I connected a 6-pin cable and retested the system. No problems.

I will be damned. I spent a LOT of time on this. (I didnt even mention the steps Microsoft told me to take to "troubleshoot" PC crashes.) I anguished about what size PSU to buy. Even though Newegg is a great company, returns are expensive.

All for nothing. All because I made a mistake with the cable 4 months ago.

Live and learn. The answer is not always more power.