A quick glance shows that the main difference between the P5K Pro and its big brother the P5K Deluxe is the chipset cooling. The Deluxe has heatpipes between the Southbridge and Northbridge, and from the Northbridge to the motherboard power supply cooler. The P5K Pro has individual coolers not connected by heatpipes, but the Pro's massive Northbridge cooler is much larger than the Deluxe's NB cooler.
A big difference but not immediately noticeable is that the P5K Pro is 1" shorter than a standard ATX board. It is still an ATX format, just shorter, missing is the front row of screw holes. We will find that there are several components located in strange places due to this.
Looking at the CPU socket area, another difference between the boards isn't noticeable, but the voltage regulators are all on the front of the Pro, there are eight of them on the rear of the Deluxe, to help keep the motherboard cool. We guess that it really works, because the Deluxe stays very cool with minimum airflow. Other than that, like the Deluxe, the Pro has most of its large capacitors located around the CPU socket.
Behind and below the CPU socket are the two biggest differences between the boards. The ATX12V on the Pro is a single 4-pin connector, rather than the 8-pin that has been on every board I have owned in probably three years. It really doesn't matter, most people never remove the plug that is always in the second four pin connector. The other is the location of the 24-pin connector. Most motherboards for the past few years have the 24-pin connector located near the rear edge of the board for ease of cable management. But, the most logical place for the connector is near the motherboard power supply, which is located behind the CPU slot, and that is where it is located on the Pro. This allows the main power traces to be much shorter, and probably makes quality control much easier. Of course the 24-pin connector is located there due to the missing 1" of PCB.
In the PCI area, we see two PCI-E x 16 slots. As other P35 motherboards, if both slots are used for Crossfire, the blue slot is x 16, and the black slot is x 4. Fortunately, the X38 and X48 chipsets allow for two full PCI-E x 16 slots, and we are looking forward to Crossfire without limitations.
Under the CMOS battery is the CCMOS jumper. Yes, this is a weird place for it, but with Asus' CPR (CPU Parameter Recall), we have not had to use the CCMOS jumper on an Asus board in months. CPR is an awesome feature, it makes a failed overclock merely an annoyance rather than the real pain it once was.
Along the bottom of the board are the aqua COM1 port, the black floppy connector.in probably the worst place we have ever seen but you really don't need a floppy anymore, the red IEEE1394 port, and three blue USB ports for six case USB connectors.
Next we see the white case header panel, and the six SATA ports. The black ports denote that they aren't to be used for boot drives. Around the corner is the red IDE port, facing away from the board.
Nothing really significant about the memory slots, other than they are located much farther down and closer to the edge of the board than most. Normally there are connectors in much of that area. The P5K Pro supports up to 8 gigs of DDR2 memory.
The first thing we noticed with the I/O panel is the inclusion of two PS/2 ports. We guess that Asus figures that someone buying an economy board is more likely to be using a PS/2 mouse or keyboard, so they added both. Missing is eSATA ports, the Asus trademark second LAN port, and optical S/PDIF.
The bundle is actually pretty complete for an economy board, 4 SATA cables, floppy and IDE cables, a Molex to SATA power adapter, Asus Q-connectors, a very handy item that prevents having to connect those case header pins directly to the motherboard, and a very cool padded I/O shield. Also included is a well written and illustrated user's manual.