Overclocking, and the not-so-good
The usage of temperature-sensing equipment on motherboards is nothing new, but the ZM6 adds a little extra which I hope will become standard practice on Abit motherboards. For one, the CPU thermal sensor is now raised under the socket, placing it much closer to the CPU itself. In fact, on some models the sensor is raised far enough to actually touch the plate covering the core, giving a more accurate representation of CPU temperature (rather than just the air around the socket.
Also, two thermal sensors are included on the motherboard. The first is mentioned above, right on the socket. The other sensor is placed between the AGP slot and the ZX north bridge chip, which should give a relatively accurate indication of system temperature. What's new is "RT2," a 2-pin header for an additional 10K Ohm thermistor, which can be purchased by the end user at any electronics store. This will allow you to place a temperature sensor wherever you wish on the motherboard. As the header is located right next to the expansion slots, it will be possible to fix a sensor onto the peripheral of your choice - an easy way to monitor the temperature of that new Rage Fury or Voodoo 3 card!
Like Abit's other motherboards, the ZM6's specialty is overclocking. We were able to run our 400Mhz Celeron at its known limit of 500Mhz flawlessly on the ZM6, and it never stuttered at 83.3Mhz x 6.0. Pushing for 600Mhz via 100Mhz x 6.0 has never been successful on any motherboard, and even with the voltage pushed up to 2.20, the system would not complete POST.
There isn't too much that's undesirable the with ZM6 (at least nothing that doesn't have to do with the chipset itself). The ATX Power connector is jammed between the socket and the parallel port, making it relatively hard to attach or remove. This is a minor problem though, and for most users a one-time hassle.
The DIMM sockets are positioned such that an average-sized AGP video card can push against the lever on socket 1 if they're left open. This almost caught us unaware the first time through, but after snapping the DIMM socket to its "closed" position the AGP card fit perfectly. However, adding more memory into socket 1 required removing the video card first, blech.
Also, the ZM6 supports Abit's trademark slew of FSB speeds, anywhere from 66Mhz to 133Mhz. However, since this is board currently targeted towards 66Mhz Celeron processors, it would have been nice to see a few intermediate clock speeds between the usual 66Mhz, 75Mhz, and 83Mhz, especially with the sketchy overclocking abilities of the newer 366/400Mhz Celeron parts.