Additional features/layout

Voltage and motherboards

Three DIMM Sockets

While the P4B266 features three DIMM sockets and boasts support for up to 2GB of memory, keep in mind that the 845 chipset only provides full support for up to two banks of memory. Therefore, if an end user wishes to take advantage of all three DIMM sockets present on the P4B266, you'll have to use single-sided memory modules on DIMM sockets two and three. While you can install a double-sided module in DIMM1, DIMMs two and three share the same row, so if you install a double-sided module in DIMM2, DIMM3 cannot be used (and vice versa).

With single-sided memory modules being phased out of production, filling all three sockets will be difficult. Most users will probably opt for expensive 1GB memory modules if they wish to take advantage of the 2GB supported by the P4B266.

The upper portion of the P4B266

New AGP retention mechanism

AGP Warning Light/Retention Mechanism

To prevent damaging the AGP slot on the motherboard, ASUS has integrated a red LED light on the P4B266. The AGP warning LED shines when the end user is attempting to install a 3.3V or SiS 305-based AGP card in the AGP slot. Most of today's newer AGP cards are 1.5V boards, so this shouldn't be a concern to most users, but it's a nice feature to have just in case. When the red LED shines the system can't be powered on.

In addition to the warning light, the P4B266 also has a retention mechanism installed on the AGP slot. The retention mechanism on the P4B266 is a bit different than previous ones in its operation. Rather than previous mechanisms that lock the AGP card into place in the same fashion as a DIMM socket, the retention mechanism on the AGP slot of the P4B266 slides on a rail to lock the AGP card into place. To lock the graphics card into place, simply insert the video card into the AGP slot as you normally would and then slide the retention mechanism over the AGP card.

Board Layout

The layout of the P4B266 is rather good, there are no major obstructions in the way of any of the PCI slots and the area around the CPU is free of any components that may hinder airflow. Since Intel has designated the area around the Socket 478 as a keep away zone, heatsink installation shouldn't be a problem on any 845 motherboard.

The floppy connector is placed in its usual location, although it's positioned at a 90-degree angle. This means that the floppy cable must be installed parallel to the motherboard, while the IDE cables are perpendicular to the board. It's a bit unusual at first, but the design seems to work well.

Notice the floppy connector

As we mentioned earlier, headers are provided for the USB brackets and in standard ASUS fare, dipswitches are provided for overclocking (although we think you'll prefer using the board's BIOS). In addition, a plethora of jumpers are located on the board for such functions as enabling the USB 2.0 controller and even adjusting the DDR memory voltage.