Overclocking and Thoughts
In our review of the Phenom II X4 955 processor, we were able to reach 3.72GHz at 1.5V using the stock cooler. Additionally, we saw idle temps of 35'C and load temps around 70'C. This time around, we used dry ice to cool the TWKR chip way down and cranked up the voltages not only to the CPU, but other system components as well.
For the results you'll see below, we used an SB/HT Voltage of 1.3V, a CPU PLL Voltage of 2.5V, a NB Voltage of 1.2V, a CPU NB VID of +0.300 and a CPU Voltage of 1.55V
First, we would like to note that we tested the TWKR with a watercooling solution to find a good starting point for our dry ice benching. Using CoolIT's Boreas TEC Chiller, we managed to hit 4GHz with no issues. That's all we could get from the chip with this type of cooling, even though the load temps topped out at only 32'C.
Then we installed the Koolance LN2 pot and after several overclocking sessions and about 20lbs of dry ice, settled in at a 4.73GHz overclock. At this speed, we were able to conduct several benchmarks in order to measure the performance gains created by such a large overclock. While the bandwidth numbers shown above are very good, we feel the 3DMark scores aren't anything to sneeze at either.
Under dry ice, the TWKR produced admirable results, but we weren't able to achieve the kind of overclocks these chips are known for. Even our watercooling overclock was surprisingly average. So what gives? The main culprit is cooling, according to AMD. For the TWKR to reach its fullest potential, liquid nitrogen or liquid helium must be used. Doing so would allow for a much higher overclock, "dropping (cooler base) temps from -70C to -188C makes a huge difference in terms of TWKR clockspeeds. You would likely get another GHz or more extra speed with LN2" we were told. The lesson here is to not skimp on the cooling when it comes to the TWKR. Once we get a hold of some liquid nitrogen or helium, we will post some more results and update this article. For now, here's a glimpse of what some others were able to achieve.