Closer Look: PCB Design

When designing the KV8-MAX3 mainboard, ABIT engineers seem to have given enough thought to the exterior of the product. Its looks is quite original, I should say.

First of all, let’s take a closer look at the CPU power supply circuit. It is a 3-channel circuit, with nothing special as far as functionality goes. On the other hand, Socket754 processors don’t require “special” power supply circuits. According to the specs, even the upcoming Athlon 64 3700+ will demand a current of 60A and a voltage of 1.55V, no more than that. Only processors with a performance rating of 4000+ and more will call for a more powerful CPU power supply circuit (with a current of up to 80A), but such processors will be installed into Socket939 rather than Socket754.

ABIT wouldn’t be ABIT if they didn’t add come “exclusive features”. This time we see the Outside Thermal Exhaust System (OTES), which is similar to the contraption installed on graphics cards of the Siluro series. KV8-MAX3 uses this system to cool the CPU voltage regulator and the socket area. OTES consists of a pipe with the open end near the processor and a small exhaust fan on the back panel of the mainboard.

Of course, OTES looks cool and effective. Moreover, it is highlighted with three red diodes when working that is why if you have a case with a transparent window in it, you should be really happy with the way your system built on ABIT KV8-MAX3 will look. As for the functional efficiency of the OTES cooling system, the situation is not so clear here.

Airflow around the MOSFET transistors that build the voltage regulator circuitry has little effect: it would be better to install heatsinks on them. However, there is nothing of the kind on ABIT KV8-MAX3. But after all, the temperature of the transistors is pretty moderate. It is about 50°C with the OTES working and the processor under a full workload, and it equals 52°C without the OTES. These 2°C are of little help really and we can conclude that OTES doesn’t contribute much to cooling the CPU voltage regulator. ABIT proponents may say that OTES helps to take warm air away from the hottest area of the mainboard where the processor, chipset and memory are located, but this is actually the job for the power supply unit. According to the ATX specification, the PSU should suck in the air from this very hot zone and blow it away from the system case. System fans are also usually installed in this area. So, in my humble opinion, the functional advantages of the OTES are quite ephemeral.