A few weeks ago we took our first look at a P55 motherboard, the Asus P7P55 Pro. However, we didn't have the opportunity to actually play with the thing properly, much less put a new Intel Core i5 CPU in it and get it up and running. Well, a few days ago Asus once again contacted us and offered us a sneak peek at another of its boards and this time we could actually plug the thing in and get a system going.
Core i5, if you recall, is Intel's brand new lineup of CPUs, expected to arrive in the next couple of months, that are based on the same basic architecture as Core i7 but with a few tweaks to make it less expensive. Specifically the memory controller has been cut-down to dual channel rather than triple channel and QPI has been replaced with DMI.
QPI, or QuickPath Interconnect is the new ultra high-speed link between multiple CPUs and the IOH (which in turn interfaces with PCI-Express devices and the ICH), that was introduced with Core i7. It is very effective and has an enormous potential bandwidth of 25.6GB/s per port but is overkill if you're not running multiple CPUs or lots of high-bandwidth PCI-Express devices, like multiple graphics cards.
So Intel has removed QPI and brought back in Direct Media Interface (DMI) (as featured on Core 2) as a generic connection for all devices apart from graphics and memory. Graphics connectivity has instead been brought onto the CPU dies itself, with 16 (or 2 x 8) lanes of PCI-Express available.
The result is a system that appears much simpler than previous motherboard layouts. Instead of the CPU/MCH/ICH or CPU/IOH/ICH arrangement of Core 2 and Corei7, Core i5 will just have two principle chips, the CPU and Platform Controller Hub (PCH). This will reduce the cost of the chips and manufacturing costs of the motherboards that go with them.
The results of these changes are evident in the motherboard we looked at where you can clearly see there's plenty of room around the CPU socket itself, just four memory slots are present, and the PCH chip is all the way over on the bottom left of the board. It's a far cleaner layout and one that should have potential to work wonders on smaller motherboard form factors like MicroATX and miniITX.