Quick Rundown on the X38 Chipset
Intel hasn't officially released this chipset to the public yet, so there is no official info on the chipset available from the Intel website. However, a lot of information has hit the market on its new features in recent times.
First off is the memory controller. The X38 chipset is derived from the P35 series so it does support DDR2 memory, however it's not officially recognised as being DDR2 compliant. Intel has big plans for this chipset as far as the DDR3 side of things go. Like NVIDIA, Intel has put its hat into the ring with the memory controller and has launched its own program for enhanced memory. NVIDIA has SLI and EPP ready memory, Intel has XMP or Extreme Memory Profile.
What is it? Basically it is an extra set of instructions on the SPD module which when running on an Intel X38 based board it gives the chipset and memory extra commands to optimise the flow of data to and from the memory, as well as allowing for a smoother overclock and more flexible memory timing adjustments for overclocking. Corsair has been the first company to get the XMP certified logo from Intel, and hopefully we will see more soon.
Now that we have covered this, we move onto something more important, the expansion slots. First off Intel has improved the PCI Express options here. The 975X was Intel's first chipset to support Crossfire which was run using two PCI Express x16 slots clocked at x8 speeds. While this worked, we have moved well beyond that now and are seeing two full speed slots and even a third running x8 speed on NVIDIA 680i boards. Intel has finally caught up and added two PCI Express x16 lanes to the X38 northbridge. That's right, they both run at full speed. This means you can run your Crossfire setup using full speed rather than two PCI Express x8 slots on a 975X board or having to use the x16 / x4 setup of the P965 and P35 boards. While Crosslink has been introduced to split the P35's northbridge x16 slot down to two PCI Express x8 slots, with the X88 it's no longer needed. While electrically the X38 is capable of running SLI, the chances of ever seeing it granted from NVIDIA are about as good as Ian Thorpe getting the bronze in Female Gymnastics.
While we are on the subject of PCI Express, the X38 chipset is also the first to support the new PCI Express 2.0 spec. PCI Express 2.0 basically doubles the data transfer rate. For example, a PCI Express x1 slot has 250MB/s in and 250MB/s out (500MB/s total transfer speed). A PCI Express 2.0 slot running at x1 has 500MB/s in and 500MB/s out (1GB/s total). What this means is PCI Express 2.0 graphics cards will be using a x16 slot 8GB/s in and 8GB/s out (16GB/s Total). Using this theory a PCI Express x4 card using the 2.0 specs would be equal to running our current PCI Express x16 spec. This can open the door for cheaper cards. While the PCI Express lanes on the northbridge are 2.0 compatible, the southbridge driven ones are all 1.0a specs. ICH10 is set to replace the ICH9 series with PCI 6 or 8 PCI Express 2.0 lanes, allowing for a third PCI Express x16 slot for physics cards to be used.