SLI hardware

Now that you understand the theory behind it all, it’s time to take a look at the hardware.

ASUS and NVIDIA made a big splash last week with their announcement that ASUS would be first to get an SLI product to market with their A8N-SLI motherboard. The A8N-SLI is a powerful motherboard, with dual Gigabit Ethernet networking (with NVIDIA firewall), dual IDE RAID with support for up to eight Serial ATA hard drives total, Firewire, 8-channel software-based audio with jack-sensing technology and an external S/PDIF-out, and of course the standard nForce4 features such as 10 USB 2.0 ports and 3Gb/sec Serial ATA.

ASUS also includes their standard features such as Q-Fan and AI NOS for overclocking, as well as POST Reporter and CrashFree BIOS2, but they’ve gone the extra mile by including an additional 4-pin power header for supplying extra power to the graphics cards, which can be helpful when running in SLI mode. ASUS refers to this as EZ Plug. Accompanying the EZ Plug connector is a red LED that will shine if the graphics card isn’t receiving enough power.

ASUS A8N-SLI board

Slots are color-coded on ASUS board

When running in SLI mode, we always used the EZ Plug connector to ensure optimal stability.

The board’s BIOS has everything a tweaker would want when it comes to overclocking. Bus speed options range from 200-400MHz in 1MHz increments, while the PCI Express interface can also be adjust from 100-200MHz in 1MHz increments. CPU voltages are plentiful, with increments of 0.0125V for precise overclocking.

The board also ships with an SLI selector card. If you recall our nForce4 performance preview article, you'll remember that NVIDIA found that for best performance, it was best to split the PCI Express lanes evenly among cards, with both running as x8 cards. When a single card is installed it runs at the full x16 spec. The SLI selector card is used to toggle between the two modes: with the selector set in dual mode, the PCI Express interfaces both run at x8, when the selector is flipped to run in single card mode, the master PCI Express interface (which is the upper connector that is colored blue on our board) runs at x16.

The SLI selector card

ASUS SLI connector (top) NVIDIA flexfit (middle) original SLI connector

Once the selector is set for dual mode, drop in your graphics cards, plug in the EZ Plug connector and power connections for the cards, and connect the two cards to each other with the provided SLI connector. NVIDIA has recently adopted a newer SLI connector that’s reminiscent of the old 3dfx SLI ribbon cable that they’ve dubbed the Flexfit connector.