Layout and features
You'd think that ASUS wouldn't bother making any cosmetic changes from its DDR2-equipped version board, other than including the DDR3 DIMM slots and associated routing, obviously.
Take a look at the above picture and then feast your eyes on the P5K Deluxe here, and you'll see that the design department were tasked to improve thermal performance.
Specifically, the P5K3 Deluxe has an additional heatpipe that connects the second passive heatsink on the VRMs - not present on P5K Deluxe - via the northbridge. Further, the upper heatpipe now extends back out to the heatsink closest to the edge of the board.
It's difficult to ascertain why the extra cooling was mandated, frankly, as the P5K Deluxe (DDR2, remember) ran just fine with a single heatpipe.
We noted that there were a bunch of other minor design changes, primarily in and around the CPU socket, but none of these will impact upon cooler placement.
What's also new are the DDR3 slots. Please note that whilst both DDR2 and DDR3 modules use 240 pins they aren't quite compatible in terms of notchings. We expect this is to stop users for inadvertently placing DDR2 in DDR3 slots in the hope that it's backwardly compatible. It isn't.
The southbridge area, though, is identical to the P5K Deluxe's, and that means the possibility of blocking-off SATA ports if an extra-long graphics card - GeForce 8800 GTX, for example - is used in the primary x16 PCIe slot.
The orientation of the expansion slots is the same, too, and that means the possibility of limiting PCI to just a single slot if two double-width cards are used in CrossFire mode.
You'll not be surprised to learn that the I/O section features an identical list of ports and sockets, as well.
