Motherboard issues
When I first built my i7 based system, I saw a ton of websites talking up the 920’s ability to be overclocked. From previous experiences with the Core2Duo I tried to get any amount of overclock with the stock cooling solution and consistently could not get get the system to post. I chalked it up to the stock cooler simply not being able to remove enough heat from the cpu.

Over the course of setting up the initial build I noticed some quirkiness with the Asus P6T being able to detect all 6GB of ram installed as 3×2GB chips. With some tweaks to DRAM voltage and memory timings I could usually get the full amount to show up. Over time this slowly led to never being able to detect all 6GB of ram, even with the latest BIOS upgrades and bumping the voltage to the 1.65 Volts required by spec on my memory. Through various searches on Google I came to find that a number of other people have run into a similar situation and the only real consensus was that switching out the board was really the only solution.

Trouble Shooting
Great, so my board is way past RMA date, considering I ordered it in the first part of the year. I started running various tests, both swapping the chips around and running memtest86. I could not identify a bad stick of ram, so that left the motherboard. As I swapped chips in and out, I finally zeroed in on the A1 memory slot being defective. So I moved the memory from A1 to B2 and booted up with 6GB of ram, but in Dual-Channel mode instead of Triple-Channel.

Final Results
Awesome! With the problem area identified and the chip moved to another bank, I was finally able to get a stable overclock from my i7 920. I was pleasantly surprised that I was able to hit 3.6Ghz with little effort after moving the memory to a good slot. My final overclock was to 3.6Ghz with memory running at 1800 FSB and with the Xigmatek Dark Knight, my OCCT temperatures after the overclock are still lower than playing TF2 with the stock cooling solution at stock speeds.

Construction
The Dark Knight CPU Cooler is very solid and makes for a rather heavy cpu cooler. It pushes the ATX specifications, leaving just enough room for me to close the side door on my Antec 300. I also like the design approach of exposing the heat pipes so they make direct contact with the CPU itself. The bottom surface of the cooler could be a little flatter to make a more solid contact with the processor itself, but a little thermal paste to fill in the nooks and crannies seemed to work out well.

Mounting Hardware
I was thoroughly impressed with the mounting mechanism for the Dark Knight on Intel boards. While I did have to remove the motherboard entirely to add the backplate, the payoff of being able to really tighten down the cooler with tension screws is tremendous. Using a corner-to-corner tightening technique, I was able to make an extremely solid heat transfer zone between the processor and the cooler.

Fan Mount
The hardware to mount the heatsink to the fan was simple and straightforward. However, the fan mounting, while clever, seems a bit fragile. I commend their efforts to make a vibration free mount, but I forsee issues if you ever have to remove the fan at any time like I did. The first time I booted up the PC, the temperature numbers were a bit higher than I was expecting and so I went to tighten the tension screws holding the heatsink to the board. Only two are accessible because the fan blocks the other two, so I had to try to remove the rubber feet from their mounting location with the board still in the case. With some patience and a ballpoint pen I was finally able to remove the lower fan mounts, but what a pain the butt. I saw the mounts stretching and knew my caveman hands were going to end up breaking one, but they all survived. I was able to tighten down the heatsink even more, for a better thermal connection, but when I reattached the fans, I only barely put the bottom rubber mounts into the slots.

*One other note, the fan is a PWM fan, which mean it should be variable. I could not however get the RPMs to drop below 2000 which leads me to believe it’s set to always run at that speed and since it’s quiet you would never notice. I should investigate my motherboard settings about this, since I have since flashed my Asus P6T and it could simply be a configuration issue.

Temperature Results
The graph below shows how the CPU temperature grew overtime with the stock Intel cooler in place. OCCT did an even greater number than Team Fortress 2 on the CPU, pushing it to 78C in less than five minutes before I got worried and canceled the test.

This final graph shows the CPU temperature over time with the Xigmatek Dark Knight fully tightened down. As you can see, the temperature difference is profound and for gaming my stability has greatly improved. One other note, around the five minute mark I lowered or turned off all fans I could to see how the Dark Knight would perform on its own. You can see that it climbed up a few degrees and when I turned the other fans back on it started dropping again.

Conclusions
Compared to the stock cooler provided by Intel, the Dark Knight is leaps and bounds better at removing heat from the most critical component of your PC. I would recommend this to anyone who needs to keep an LGA775 or LGA1366 mounted CPU cool.

When I initially was putting this system together I didn’t expect to do any overclocking. The hardware was already pretty fast and would play any games out now and rocked my primary concern of Team Fortress 2 without breaking a sweat. Then I tried overclocking just to see what performance gain I could achieve and was pleasantly surprised that I could take the processor to 3.6GHZ on stock cooling.

This got the itch started and I began adding on parts to bring the temperatures of the hardware down to reasonable levels. First I replaced the cooler with an Arctic Freezer Pro 7 CPU cooler and finally replaced the case completely to increase overall airflow.

The Sonata III had 2 120mm fans running at full 2000 RPM and was removing 79 Cubic Feet / Minute of hot air from the case. The problem was, the intake fan was 4-5 inches inside of the case and it struggled to replace the hot air with cool air from outside the case. With both of these fans running at 30DB each, it was loud and wasn’t doing a very good job of cooling the system.

The tables for fan speeds are only estimates due to the fact that I use SpeedFan to automatically monitor temperatures and adjust fan speeds based on my desired temperature specifications.

The Antec 900 case has two fans in the same positions as the Sonata III, but adds 4 more fans to the overall system, including a huge 200mm exhaust fan situated directly above the processor. I am not going to include the internal fan in the same position as the Sonata III because it doesn’t directly intake or exhaust outside air anymore.

Overall The Antec 900 case is great for anyone who wants to build an air cooled overclocked system. I would recommend it to anyone that’s interested in keeping the airflow high while keeping the noise levels down.

The memory is slightly overclocked, but now that there is enough air flowing over the head spreaders it’s not flaking out like it was in the Sonata III.