MSI X48 Platinum: Four PCI Express x16 Slots to go Please....

Board Features and Layout (Continued)

In a surprising twist of events MSI has opted to design the X48 Platinum to allow for a total of four x16 PCI-Express cards to be installed simultaneously, making this board rather unique in this respect. The blue slots are directly connected to the X48 MCH, making them PCI-E 2.0 compatible and the right choice when configuring the system for standard CrossFire operation. The bottom two yellow slots are able to accept x16 cards mechanically, but each only provides for x4 link speeds from the installed device to the Southbridge.

This particular PCI Express expansion topology is different than some other X48 boards with only one additional PCI-E x16 (x4 electrical) slot hanging off of the ICH9R. MSI does this by adding a third-party chip to the X48 Platinum which bridges one of the available PCI-E x1 lanes offered by the ICH to an x4 electrical link state which is seen by the lower yellow PCI-E slot. One could argue that the performance potential of such a setup is marginal at best seeing as how the device installed in the last PCI Express slot is seriously bottlenecked by this configuration. Although the slot device is configured for x4 operation, the bridge chip is only able to communicate with the ICH at x1 speeds. Furthermore, this downstream device must contend with all other PCI Express traffic passing through the ICH to the MCH over a single x4 link, which would most likely include another x4 device residing in the first yellow slot. However, regardless of the shortcomings we may note, the additional capabilities provided by this setup are clear: many x16 devices are only capable of down-training to speeds of x4 or x8 and without this bridge chip the last x1 lane would be otherwise useless.

Seeing as how MSI has managed to provide this extra feature while still keeping the overall board cost low, we can hardly fault them for trying to do right. The dual PCI-E 2.0 x16 lanes by themselves provide more than enough transfer bandwidth for even the most data-hungry video cards. ATI's newly release Radeon 3870X2 is already a dual-CrossFire setup on one card - adding a second card to the other primary graphics slot brings the potential of quad-CrossFire action (drivers pending). Because of this we believe it is safe to assume that any cards that find home in the yellow slots will most likely be more forgiving when it comes to interrupts in maximum throughput or associated latencies. For example, this board makes possible the option to install an additional card for physics as well as a PCI-E disk controller card that requires more than a single x1 link to operate. This alone is almost enough for us to consider the X48 Platinum as a strong candidate for a workstation motherboard.

Here is a better look at the heatsink covering the third-party bridge chip we previously mentioned. We can also see four of the six SATA ports attached to the Intel ICH9R Southbridge. The remaining two ports provided by the ICH are located on the motherboard's back panel as eSATA connections, giving the user the ability to run an external RAID array without the need for any additional hardware. The last two remaining ports - one black, one red - are attached to the add-on Marvell controller and support JBOD and RAID 0/1 configurations.

Onboard power and reset buttons are provided for the user than wants to control their board without the use of a chassis, and an array of status lights can be seen just to these left of these, removing the need for a case altogether.