Intel's X48 Express chipset is designed for the latest generation of multicore 45nm Socket 775 Intel processors. It officially supports Front Side Bus speeds at high as 1600MHz (800/1066/1333MHz inclusive), although the Intel X38 could manage this when overclocked. The Intel X48 Express is a paired with Intel's ICH9 series of Southbridge chipset. The Southbridge chipset used with the ASUS P5E3 Premium motherboard in this review is the ICH9R model, so the board supports RAID via Intel's Matrix storage technology.

Memory support expands to DDR3-2000 (XMP) care of Intel's Extreme Memory Profiles. Intel XMP is set of pre-defined memory SPD profiles that allow standard DDR3 memory to be overclocked via the BIOS automatically by selecting the appropriate profile, or via a tuning utility in Windows.

Up to a maximum of 8GB of unbuffered ECC/non ECC DDR3-800/1066/1333/1600/1800/2000 (XMP) memory in a dual channel configuration is supported. However, to run memory modules at 1600MHz XMP only one pair of DIMMs may be installed. If two memory modules per channel are installed, the Intel X48 will accommodate DDR3-1333/1067/800 modes only.

The X48 Express is the second Intel Northbridge to come with a heatspreader. This allows the X48 Express to use a smaller heatsink and still keep the Northbridge chipset cool. Here's a quick look at how the X48 Express stacks up to the P35 Express and X38 chipsets. Apart from the speed increases, inclusion of PCI Express 2.0 and the focus on DDR3 memory alone, there are just a few extra ports.

Intel Chipsets Feature Breakdown Intel X48 Express Intel X38 Express Intel 975X Express Intel P35 Express Intel P965 Express CPU LGA775 Core 2 Quad LGA775 Core 2 Duo LGA775 Core 2 Duo LGA775 Core 2 Duo LGA775 Core 2 Duo Front Side Bus (FSB) 1600/1333/1066/800 MHz 1333/1066/800 MHz 1066/800 MHz 1333/1066/800 MHz 1066/800/533 MHz Intel XMP Memory Yes Yes No No No Dual Channel Memory Support DDR3 2000/1800/1600 (XMP) 1333/1066/800 DDR2 1066/800/667 DDR3 1333(unofficial)/1066/800 DDR2 800/667/533 DDR2 1066/800/667 DDR3 1333(unofficial)/1066/800 DDR2 800/667/533 Maximum Memory Capacity 8GB 8GB 8GB 8GB 8GB Integrated Graphics - - - - - PCI Express 2.0 x16 2 2 2 1 1 PCI Express x1 6 4 4 6 4 Intel Matrix Storage Technology Yes Yes Yes Yes Yes SATA/IDE HDD 6/0 6/0 4/1 6/0 6/0 SATA Speed 3Gb/s 3Gb/s 3Gb/s 3Gb/s 3Gb/s RAID 0, 1, 5, 10 (with ICH9R) 0, 1, 5, 10 (with ICH9R) 0, 1, 5, 10 (with ICH7R) 0, 1, 5, 10 (with ICH9R) 0, 1, 5, 10 (with ICH8R) Hard Drive NCQ Yes Yes - Yes Yes USB 2.0 Ports 12 12 8 12 8 PCI Masters 6 6 6 6 6 Audio High Definition Audio (Azalia) High Definition Audio (Azalia) High Definition Audio (Azalia) High Definition Audio (Azalia) High Definition Audio (Azalia)

As many as two PCI Express x16 videocards, each with a full 16 PCI Express lanes can be used with X48-based motherboards. There are six PCI Express lanes associated with the ICH9R Southbridge and a 2GB/s I/O bus between the Northbridge and Southbridge chipsets.

The ICH9R supports six 3GB/s Serial ATA II channels (which support RAID modes 0, 1, 5 and 10) as well a 7.1 channel Intel Azalia high definition audio, 12 USB 2.0 ports in total (split between headers and the I/O slot), six PCI Express x1 lanes, and an integrated Intel Gigabit MAC that runs through the PCI Express bus specific to this chipset.

ASUS has an included JMicron IDE controller so you can still plug in your old IDE DVD-ROM to install Windows, since the ICH9R Southbridge doesn't support legacy IDE drives natively. Lastly, the chipset can work with a Trusted Platform Module in case you want to enable cryptographic protection on your motherboard.

System Power Draw Comparisons

ASUS also includes its proprietary power saving Energy Processing Unit (EPU) on the P5E3 Premium motherboard. The EPU monitors processor and system load, and can disable four of the eight power-phases dynamically when they're not in use. This two-step power design can increase the system's overall power efficiency overall without compromising overall performance.

Like power saving schemes from other manufacturers, the ASUS EPU doesn't make a dramatic difference in power consumption (generally a 2-4% decrease in total system draw when enabled), saving even a few watts of power can really add up over the lifespan of a motherboard.

Next up is the photo gallery of the ASUS P5E3 Premium/Wifi-AP.N board as PCSTATS goes in for a closer look!