The Core 2 has been in a position of dominance over the Athlon 64 X2, and later the Phenom, for some time now and Intel has enjoyed the fruits of its superiority. Both dual and quad core models have been very successful, and Intel hasn't felt the need to upgrade clock speeds since the 3.2 GHz Core 2 Extreme QX9770. The only potential challenge has been the onboard memory controller of the AMD processors, and its ability to ramp up memory performance and bandwidth higher than Intel's traditional, chipset-based architecture.
One way to close the gap has been to upgrade memory to high-speed DDR3, and beat AMD that way. Intel took that route with the X38, and then filled in the performance and mainstream chipsets with DDR3-capable chipsets, while being sure to support DDR2 should vendors wish to employ it. Their latest enthusiast-level chipset, the X48 Express, is very similar to the X38, almost like a final revision to that chipset.
The X48 Express is currently Intel's top-end enthusiast platform, and includes all the features and performance bells & whistles you would expect. Processor support covers the gamut of Core 2 Duo, Quad and Extreme 45nm and 65nm models, as well as Pentium dual-core and Celeron LGA775 models. Front-side bus speeds ranges from 800 MHz to 1600 MHz, and although the X38 unofficially could handle 1600 MHz processors, the X48 is the first, and only, Intel desktop chipset to officially support this FSB speed.
The X48 uses DDR3 memory, and although Intel does not expressly mention DDR2 as an option, several manufacturers have produced DDR2-based X48 motherboards. The X48 also upgrades official dual-channel DDR3 speeds from 1333 MHz on the X38 to a full 1600 MHz, and with 25.6 GB/s of memory bandwidth. These are only "official" speeds, and some high-end motherboards have taken the defaults a bit higher. Intel also offers Fast Memory Access on the X48, which optimizes memory bandwidth, while lowering latencies. Flex Memory Technology, where different sized modules can be used in dual-channel mode, is also supported on the Intel X48 chipset.
The Intel X48 Express Northbridge provides up to 12.8 GB/s of CPU bandwidth, while supplying a full 2.0 GB/s chipset link. The chipset supports the Intel Extreme Memory Profile (XMP), and compatible DDR3 will be automatically configured with optimum memory settings. The X48 ships with the ICH9, ICH9DH or ICH9R Southbridge, and offers PCI Express 2.0 graphics, with support for ATI CrossFire in dual-GPU implementations. Other features include PCI Express peripherals, Intel High Definition Audio, Intel Gigabit LAN, Serial ATA 3.0 Gb/s & eSATA, Intel Matrix Storage Technology, Intel Turbo Memory (ICHR), and Intel Quiet System Technology.