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CeBit 2005: MSI 'digital' SLI bridge

Earlier this week, we went to see NVIDIA\'s press conference, where they announced the highly-anticipated NForce 4 SLI solution on the Intel Platform. Unfortunately, the performance doesn\'t appear to be quite there in comparison to the AMD solution, which we know has surprised the firm in terms of sales, with half a million boards scheduled to ship by the end of this month.

Regardless, MSI, one of NVIDIA\'s NForce 4 for Intel launch partners, are displaying their implementation of the chipset on its stand at CeBit. This motherboard is interesting in many ways, but the part that interests us most is regarding something that MSI themselves are keeping fairly quiet about at the moment.

The P4N Diamond features a world-first digital SLI connection. The four current NForce 4 SLI motherboards that are available on the AMD platform, along with several unreleased motherboards that we have seen here at CeBit feature a \'bridged\' solution for changing the mode that the two PCI-Express x16 slots operate in. DFI used a large batch of jumpers on their nF4 SLI series of motherboards, while the other three AMD solutions from ASUS, Gigabyte and MSI all use a switchable \'card\' that changes the PCI-Express lane configuration.

MSI\'s latest P4N Diamond motherboard controlls this configuration via a digital connection that is all handled by the motherboard\'s BIOS - there is no user interaction required at all. Depending on whether the motherboard has one or two video cards connected determines which mode the PCI-Express lanes operate in. This means that if one video card is installed in the system, the slot is given a full allocation of an x16 lane; when two video cards are installed, the BIOS automatically allocates each x16 slot with the equivalent bandwidth to a PCI-Express x8 slot, allowing for SLI to be set up with minimal user configuration.

The great thing about this is that you can interchange from a single card to a dual video card configuration without having to change any \'hard\' settings on the board itself - this SLI solution is completely \'jumperless\', so to speak. Unfortunately, we could not get pictures of the actual layout of the PCB, as MSI have covered the section of the motherboard over with a sticker for the time being. However, we understand that there are two parallel rows of IC\'s underneath the sticker that control the PCI-Express lane configuration. We understand that MSI are awaiting a patent for the technology before revealing what is underneath the sticker in between the two PCI-Express lanes.

We\'ll leave you with a few pictures - you can just about see the start of the two rows of IC\'s at the I/O end of the PCI-Express slots.

- Tim Smalley







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