865PE/875P Motherboard Roundup June 2003 - Part 1: 20-way Shootout

Another option we thought worth going into a little bit of detail on is Vcore support. Vcore is adjustable in the AX4C Max's BIOS up to 1.850V in 0.0250V increments. Even though 0.0250V increments aren't as fine as other adjustments in other motherboard's BIOSes, 1.850V is an excellent ceiling for AOpen to set. Overclockers will have all the room they need to ratchet up their FSB. On that note, we should mention that the AX4C Max undervolts quite a bit according to CPU-Z (version 1.18) and the BIOS PC Health section. We noticed an average undervolt of about 0.060V-0.065V. Therefore, you will want to set your Vcore to 1.60V in the BIOS if you want your 800MHz FSB CPU to run at its real default Vcore (1.525V) or 1.625V if you have a 3.0C processor (default Vcore for this CPU = 1.55V).

Despite all the positive things we have to say about the AX4C Max, we did run into some heat issues with this motherboard. The first and most significant of the heat issues with the AX4C Max was the active cooler used to cool the 875P North Bridge. This heatsink was still very warm to the touch compared to other North Bridge heatsinks. Secondly, despite the fact that we didn't have time to measure exactly how hot our 3.0C (HT enabled) was running, the CPU HSF was definitely much warmer to the touch installed in an AOpen AX4C Max motherboard than with any other P4 motherboard tested here today.

The third and final heat issue came from the massive passive heatsink used to cool one of the voltage regulators to the left of the North Bridge. This heatsink was not warm, it was burning hot, so hot that we could not touch this heatsink for more than 4 seconds without burning an index finger. AOpen needs to address the AX4C Max's layout, as it is simply not adequately dissipating heat.