The mainboard is the basis of any small form-factor PC. The manufacturers have to develop special mainboards, since those of other form-factors do not have the necessary dimensions and functions. So, the mainboard our “cube” is based on has to combine small size with huge functionality similar to “grown-up” Full ATX mainboards. Designing a mainboard for a barebone system is a truly hard task for the developing team. Let’s see how well the AOpen engineers coped with this task.
The AOpen XCcube EZ65 PC uses an AOpen UX4SG-1394 mainboard:
You won’t find a description of this mainboard at the AOpen website, since it was developed especially for the XCcube. The board features the Intel 865G chipset, which mostly determines its functionality scope.
This mainboard supports Socket478 processors with 400/533/800MHz FSB, with and without Hyper-Threading. You should note that the CPU voltage regulator circuit is not adapted for older Willamette-based CPUs and you can only use processors on Northwood core in the AOpen XCcube EZ65. However, AOpen didn’t hesitate to announce processors with a frequency of up to 3.2GHz. I was all doubtful about a processor with such high heat dissipation and power consumption to function properly in a cube-like system with a 220W PSU. My doubts flew away as soon as I saw the AOpen XCcube EZ65 working with a Pentium 4 3.2GHz without any stability-related issues.
It’s all standard with the supported memory. You can slip DDR400/333/266 SDRAM modules into the two DIMM slots available. If the modules are identical, the mainboard works in the dual-channel mode. We should give credit to the engineering team from AOpen who made sure that the AOpen UX4SG-1394 works not only stably, but also fast enough. I was much pleased to see something similar to PAT (Performance Acceleration Technology) in the BIOS Setup. In AOpen’s terms, it is called Performance Boost Engine.
The upgrade and expansion capabilities of the mainboard are naturally limited by its small size. It has only one AGP 8x slot and one PCI slot. On the other hand, with all those controllers available in the AOpen UX4SG-1394, you will hardly need anything else. The i865G chipset used in the mainboard has an integrated graphics core aka Intel Extreme Graphics 2. Although this core doesn’t allow playing modern 3D games because of its limited capabilities and speed, it is strong enough for working in office applications, playing videos and running previous generation games. If you want something more, just upgrade the barebone with an add-on graphics card. The AGP 8x slot is located at the edge of the PCB, so you can only install cards that don’t require extra space for their cooling systems. This limitation doesn’t seem to be much important, though.