I’ve been known to play a PC game or two or three… however recently I came to the decision my gaming PC at home (the rig) was feeling a little out dated.

Prior to my recent upgrades I was running the following,

• Intel Core i7 875K 2.93 GHZ LGA1156 CPU Processer
• Gigabyte GA-P55M-UD4 p55 LGA1156 Motherboard
• G Skill 16GB (4 x 4GB) PC3 10666 (DDR3-1333) Memory
• OCZ Vertex 2 120GB SATA2 SSD
• Western Digital 3.5″ Velociraptor 600GB SATA Hard Drive
• ASUS Nvidia GTX480 Graphics Card
• Fractal Define R1 Case
• 600W Power Supply
• Noctua NH-U12P CPU Cooler

This was purchased in late 2010, so about 2 and half years old now. So in the context of gaming hardware this was ancient, but still it was doing a pretty good job of keeping up. I spend a lot of my gaming time playing Battlefield 3, however I was not able to play this game on the full resolution of my 30 inch Dell monitor (2560 x 1600) so I was keen to upgrade to get this running smoothly.

Further I knew Crysis 3 was only around the corner so a began my grandeur plan to upgrade my PC.

I started doing some research and eventually got onto the idea of running two video cards together using SLI (Nvidia). SLI basically means you have two Nvidia graphics cards for the same model connected together, then you will use the graphics processing power of both cards, instead of just one.

After some fluffing around, a broken motherboard (don’t ask!), a few swear words, karma and a few weeks, I had upgraded my CPU, Motherboard, Powersupply and an additional GTX480 Nvidia graphics card to SLI.

After putting it all together, getting my OS, Apps, Files etc migrated across I finally could get into gaming.

So I fired up Battlefield 3 with graphics settings on the highest, full resolution and began playing. Simply put, it was awesome.

However after about 1 hour, my PC rebooted out of the blue.

During my initial fluffing around I had similar issues when playing games the PC would reboot after a random period of time. However previously it was after a few minutes, not 1 hour. In that case I had changed my PWS from a 600W power supply to a 900W power supply, so I knew it wasn’t the power requirements (I even used a power meter to monitor the watt draw from my PC).

My next assumption was that it was the graphics cards overheating after a period of use. So I monitored the temperatures and continued to play my games. I was noting the cards were getting to around 80 degrees Celsius around the time I was getting reboots. This was well within the max operating temperatures of the graphics card (120 C).

I still believed it was temperature related at this point in time, so I turned the aircon on in my apartment and continue to play. Interestingly I was able to play for longer this time without an issue, but still at some point my pc would randomly rebooted. By this point I was convinced it was the graphics card(s) overheating due to a fault or something like that.

I had checked memory temperatures, CPU temperatures, motherboard temperatures and they were all fine!

I continued to put up with the issue for 4 weeks as I did not have a lot of time to allocate to troubleshooting this further as I had covered all the angles I could think of.

Then Crysis 3 came along, I installed it and started playing and the reboots continue to occur which was starting to frustrate my considerably. Still believing it was heat, I moved my entire PC from under my desk, to onto my desk (making an epic mess in the process) and started playing again.

I then played for 3 hours with no issue, no reboots and no problems. Graphics cards were running a bit hot, around the 90 degrees Celsius range but still running strong!

So I sat back and thought what is the difference between having my PC on the floor and on the ground.

Then it finally clicked! In the Fractal Define R1 case, the power supply is on the bottom of the case. So the big fan of the power supply blows down through the base of the case. When the case is on the ground, the carpet is blocking that airflow completely, so the power supply overheats when it is under heavy draw from the two graphics cards.

So I put the theory to the test, I moved my PC case back under neath my desk, but raised it up off the carpet.

No reboots!

One annoying note, there is no way to monitor the temperature of a power supply through the computer, there are no sensors there. Maybe something to consider for the future!

Lessons Learnt?

• Air flow is important for ALL parts of our PC (CPU, Graphics Cards, Hard Drives AND Power Supply).
• Be patient and work through all possible angles.

I hope this will help someone in a similar position figure out their heating / reboot problems!

If you’ve had a similar issue or have a question feel free to leave a comment.