Weíve finally come around to do some further tests on a 3.4GHz Pentium 4 processor with the new 90-nm Prescott core which just arrived at our doorstep. We didnít bother looking into its performance too much as weíve already taken at look at how a 3.2GHz Pentium 4 with Prescott core performed in our recent ĎThe next Pentium 4 processor, Prescott arrivesí article. Besides that article, which looked at the mere performance benchmarks, we couldnít resist also writing a provoking column about Intelís latest sibling in which we raised the question why Intel gave it a Prozac subscription due to itís lacking performance in comparison to the older Northwood core. However, neither the article nor the column addressed an issue which has been topic of much debate and discussion lately, and thatís the power consumption and heat output of the Prescott processor.
Fig 1. The Akasa copper heatsink with speed adjustable fan that was used for overclocking.
Our 3.4GHz Pentium 4 processor came with the official Intel reference heatsink, which is rather large, and also rather noisy at high speeds. It managed to keep our 3.4GHz Pentium 4 processor below 60 degrees celcius in our testbed though, without running at full speed all the time. Unfortunately our testbed is far from how a processor would normally be used, as it is always operated with the cover off, with plenty of case ventilation. Thus we decided to try this new processor in a typical work environment, a mid-tower case with all the lids in place and fastened securely. It then quickly became apparent that the Prescott was already idling at over 50 degrees Celsius, which meant the fan was spinning at full speed most of the time. But that wasnít all; by stressing the processor to 90Ö100% usage the temperature continued to rise above 60 degrees Celsius and finally settled at 69 degrees Celsius.
Fig 2. Temperature reading of our digital multimeter measured at the base of the heatsink.
Sizzling hot is how weíd described that, as normally a processor temperature of over 60 degrees Celsius isnít something weíd recommend. We then proceeded to see how the Prescott fared with a little overclocking and we quickly found out that at a mere 5% overclock the temperature would soon be touching upon 70 degrees Celsius, too hot to our liking. Fitting a different cooler, in this case an Akasa King Copper, which basically is a massive, fine finned, copper heatsink, didnít really improve things much. The resulting temperatures, with the selectable fan speed at maximum, were about 5 degrees lower. Nevertheless we managed to clock it to a maximum of 3.75GHz at default core voltage and temperatures approaching 70 degrees Celsius. It could go a little further, with a bump in core voltage by 0.1-volts we managed to touch 3.8GHz, but quickly shut the system down as the temperature was at 171 degrees Fahrenheit, or 77 degrees Celsius in a matter of minutes. That, by our judgment, is nearing supernova temperatures and doesnít show much headroom for current Prescott processors.