This series is a review of the overclocking limits of the Core i7 860 using stock cooling, and the effects of Hyper Threading on that limit. All parts used in this test are brand new. Each part was carefully selected to work in harmony together. Your results with the Core i7 860 might vary slightly based on your configuration. If you are looking for new system, however, you will be incredibly happy with this particular set of components.
Before we look at the hardware, let me define ‘overclocking limits.’ While you can achieve blazing speeds with the Core i7 860, especially with the ASUS p7p55d series of boards, the stock cooler can simply not handle anything more than a slight increase in voltage. The stock voltage of this Core i7 is 1.145V. Bumping this up by just 0.135V resulted in the system temperature jumping to 100°C within 15 seconds of Prime95 torture.
For the sake of this study, the ‘overclocking limit’ is described as the the maximum frequency/voltage that can handle 100% load at safe operating temperatures. While this CPU will easily do 4 GHz (ran fine at idle for me with ram at 2000MHz also), the temperatures go wild with the stock cooler. A big contributor to this heat is Hyper Threading. In our case, we found that turning HT OFF resulted in temperatures 20 degrees cooler while under load. With that out of the way, let’s take a look at our hardware.
If you are not familiar with it, the Cooler Master HAF-922 is an incredible case. If you are in the process of picking one out, I highly recommend you check out this great video review from 3dGameMan.com. This case is incredibly well made. Solid metal, mobo retention plate cutout, intake filters, dual 200mm fans that make almost no sound, tool-less bays, and plenty of space for the large GTX 470 or aftermarket CPU cooler.
Also note that this system is somewhat “green.” I’m very proud of the OCZ 80Plus Silver certified PSU. If you are not familiar with 80Plus, you can see what it’s all about at 80Plus.org. In addition to power, I opted for some great looking low-voltage Eco RAM from G.Skill. This ram only uses 1.35V and comes in various speeds/timings. For this system we opted for the tightest timings, which came in chrome-laden DDR-1333 at 7-7-7-21-1T.
I wont let this turn into a debate over speed vs. timings. I’ll simply point out again that this is an overclocking study, so it makes sense to get tighter timings with lower speed so that we have plenty of overclocking headroom. Obviously, a lot of overclocking scenarios tie the memory and CPU frequencies together. Initially, I second guessed myself at not getting the low voltage DDR-1666 version.
After seeing this stuff in action at 2000 MHz, though, any fears I had were laid to rest. One irritating note – this DDR looked like it was white in Newegg pictures. Chrome is still great looking, especially with this motherboard, but I was excited about white.
Finally, we come to the ASUS P7P55D-E Pro motherboard. This series has been extremely well received, and is my fifth board from ASUS. This particular line, denoted with -E, is new in 2010 and features the first real USB 3.0 and SATA 6GB/s. This future proof board has plenty of flexibility, rock-solid quality, and full-featured bios provided by American Megatrends.
Let’s turn it on and take a look at stock performance and temps using CPU-Z.