With the high end X38, is Intel offering a new chipset that is supposed to replace the i975X? What’s new compared to the classic P35 Express?
The differences between the P35 Express and X38 are confined to the MCH (Northbridge). In terms of the ICH, we in fact find the version 9 which is connected to the X38 via a DMI bus at 2 GB /s (1 GB /s in each direction). In its basic version, it manages four PCI Express ports, has an integrated Ethernet Gigabit controller and controls four AHCI 3 Gbits /s type SATAs. In its DH version, it manages a total of six SATAs, while the « R » allows managing Matrix Storage (RAID 0/1/5/10), as well as two innovations, Rapid Recovery and Turbo Memory on its six SATA ports. Also, note that the SATA ports of the ICH9-R are Port Multiplier compatible and can therefore be doubled via an additional chip in order to support several peripherals.
However, let’s take a look at the real differences between the X38 and P35 Express. For the latter, PCI Express management is limited to a single PCI-Express x16 port. For this reason, those cards equipped with two PCI-Express x16 ports actually have one port connected to the MCH and which is wired in x16, and a second relayed to the ICH which is wired in x4. The performances of this second port are thus largely inferior and to install a good graphic card in a multi-screen or CrossFire (SLI can’t be activated on Intel chipsets) configuration doesn’t give the best results.
With the X38, Intel decided to shift into high gear. First of all there is management of a total of 32 PCI Express lanes, or two 16 lane ports, and also its lanes are within the 2.0 norm. In its version 2.0, the PCI-Express speed is doubled to attain 500 MB /s of data speed per lane in each direction, or 8 GB /s on a single x16 port. Note that while they should soon arrive, PCI-E 2.0 graphic cards aren’t yet available. Either way, in all situations and in the beginning the performance gain will be inexistent for classic use.
The other differences between the P35 and X38 are more subtle and less documented. Intel mentions an improved memory controller and says that they have pulled the « overspeed protection » that was present on the P35. Let’s get the more practical side of things and see how this chipset does in tests.
For this test, ASUSTeK provided us with a P53E Deluxe in its version 1.03G. The motherboard takes on the X38’s specifications and ASUSTeK as usual has added some chips: a FireWire controller provided by Agere, a Realtek PCI and Marvell PCI-E Ethernet Gigabit controllers (ASUS having decided not to use the one integrated to the chipset) and a JMicron chip devoted to management of a PATA and two eSATA ports. It’s now the trend to have passive cooling provided by a system of copper heat pipes and fins.
Taking apart the system gives us a glimpse of an innovation on the chipset level in the form of an IHS as up until now the die was «naked». The IHS has two purposes, on the one hand to redistribute the heat given off by the chipset onto a larger surface, and secondly, to protect it from a clumsy dismantling of, for example, a waterblock. Once the motherboard is installed and started, we were impressed by the number of adjustments offered by the bios as well as their finesse. In addition to a large number of memory settings – maybe even too many – ASUS offers direct access to the FSB Strap as well as to various precise voltages. For example, for the northbridge this can be adjusted between 1.25 and 1.91v by increments of 0.02v.
The bios is compatible with Intel Extreme Memory which is an extension of SPD of DDR3 memories destined to function with higher settings. Memory manufacturers can also offer standard SPD settings for their modules and a second more aggressive set for those who like to fiddle with adjustments. However, note that this group usually does this on the memory level and the interest of such a function is rather limited in our opinion.