Las Vegas (NV) - A video appeared last Thursday on the YouTube channel AMDUnprocessed showing the processes and techniques used to supercool an AMD Phenom II CPU to well below -200 degrees Celsius, while pushing the CPU and motherboard to 6.5 GHz. The best result was achieved by Sami Makinen of AMD taking a 6.3 GHz overclocked Phenom II-powered Dragon system to a world-record of 45,474 3DMarks in 3DMark 05.
The team brought 500 liters of liquid nitrogen and 500 liters of the much colder liquid helium to a location in the desert just outside of Las Vegas. By cooling down the system first with liquid nitrogen and allowing the coolant to evaporate away, and then continuing the cooling with liquid helium, a temperature of about -232 degrees Celsius was achieved. Liquid helium exists at about 3 Kelvin, or about -270 degrees Celsius.
AMD used their new Dragon platform for the motherboard. They began overclocking at 6.3 GHz on a 286 MHz bus, HyperTransport link of 2.28 GHz and the on-die memory controller operating at over 4 GHz (compared to normal 1.8 GHz) with system memory at 572 MHz. At these settings the system maintained about -220 degrees Celsius. It generated a 3DMark score of 44,988 3DMarks.
Next, they jumped up to the fastest speed they'd been able to achieve for the CPU: 6.509 GHz on a 283 MHz bus with 23x multiplier, and HT Link of 2.264 GHz. The initial temperature at these settings was -242 degrees Celsius, though during maximum processing it tipped up into the -190s.
Makinen noted that the liquid helium used for cooling evaporates very quickly due to the temperature disparity. The 250 liters used for this particular test, they said, "gives us only about 90 minutes of benchmarking." Makinen also said that "the CPUs" have not been able to run at such extreme cold temperatures previously. As such, he classified this attempt as "an experiment" to see if they could get more scaling by using liquid helium.
AMD includes this important warning at the start of the video:
"Overclocking and extreme cooling is certain to void your hardware warranties and could cause serious damage to your PC hardware. We burn through motherboards, processors and graphics cards at an alarming rate doing it. AMD does not recommend pouring liquid nitrogen on your head or on your friend's head. Liquid helium is incredibly dangerous in untrained hands and one of the coldest substances in the universe. Only the most experienced safe and methodical overclockers should every even think of attempting something this extreme." (sic)