Elitegroup's P6BX-A+ board caused quite a few problems until I could start testing it. With the first BIOS the board was unable to run 66 or 100 MHz FSB clock, instead it only ran 68 or 103 MHz. c't-Magazine had the same problem, but their BIOS allowed to manually switch to 66 or 100 MHz. The BIOS I had was stubbornly sticking to the 'turbo mode', so that I first couldn't do any benchmarking tests. The second BIOS I received solved this problem, but I ran into another one. In the process of trying to adjust the BIOS for best performance I had enabled 'AGP Bus Cacheing'. This leads to a complete inability of using the 3D hardware accelerator of any AGP card. You can imagine that it took me a while to find what the reason for this strange occurance was. Thus keep your hands off 'AGP Bus Cacheing', leave it DISABLED!
Finally the board could be tested and it showed above average performance. It also didn't have the slightest trouble with any of the SDRAMs I used for testing, including a successful pass of the PC66 SDRAM test at 112 MHz. The P6BX-A+ comes with some really fancy connectors for the IDE and floppy cable. Clamps on both sides ensure a save connection.
The compatibility test turned out to be quite a bit of a pain however and the reason for it is so sad. Elitegroup decided that it is not necessary offering a BIOS setting for the disableing of the USB IRQ. Thus the USB port is blocking one IRQ permanently, regardless if you use it or not. As you can imagine, this caused quite a bit of trouble in my 5 card configuration. After 2 hours of trying I finally got all the cards to work. You can read what it took in the compatibility report.
Summarizing the occurances leaves a mixed impression. The P6BX-A+ does certainly have what it takes to be a good motherboard. However, unnecessary BIOS features as 'AGP Cacheing' and the lack of 'Disable USB IRQ' are currently the reason why this board is a potential trouble maker. If Elitegroup should change the BIOS, the board could easily make the recommendations list, because it runs stable and it runs fast.
Elitegroup has sent me a BIOS that will now let you disable the USB IRQ. 'AGP Cacheing' was removed from the setup menu. I will retest this board soon, but for now it looks as if the problems were resolved.