Very cheap yellow coolers are often used with the Bitaxe, which tend to cause the processor to overheat. With the alternative and very affordable 40x40 cooler made of aluminum, which is actually intended for Northbridge cooling, you can easily cool the Bitaxe. However, the assembly is a bit fiddly and the distance between the ASIC and cooler is too dangerous because pulling the screws too tight can cause the processor to malfunction.