For AMD fans, your current performance minded PCI Express options are really between VIA's K8T890 series and the nForce 4 line. Truth be told, K8T890 based boards are still relatively rare, at least when compared to the sheer number of nForce 4 offerings. Of the nForce 4, a lot of the press goes towards the nForce 4 Scalable Link Interface (SLI), and for good reason. Not only is there one PCI Express x16 slot, but there are two (though they become x8 slots in SLI). , if you have two SLI certified video cards to go with a SLI capable motherboard, you can experience a substantial increase in performance.

Of course, you'll still need quite a bit of cash to fork out in order to fully build a SLI rig. To begin with, you need a supported motherboard, as well as two video cards (limited to the 6600GT, 6800GT/Ultra, all with PCI Express interfaces and be within the same class in SLI mode) and perhaps a new Socket 939 based CPU if you don't already have one. SLI is designed to be scalable though, so you don't have to own two video cards right off the bat. In terms of future growth, the platform is strong as you can add a second, identical GPU to improve performance if your games are running slow.

Today, we'll be looking at the ASUS A8N-SLI Premium, which is ASUS' flagship SLI board. It has all of the nForce 4 SLI features, plus some items thrown in by ASUS for good measure. If you're considering a move to the nForce 4 platform, you'll want to read the rest of the review.

CPU	AMD Socket 939 FX/64
Chipset	NVIDIA nForce4 SLI
Memory	- 4 x 184-pin DIMM Sockets support max. 4GB DDR400/DDR333/DDR266 ECC/ non-ECC un-buffered DDR SDRAM memory - Dual Channel Memory Architecture
Expansion Slots	- 2 x PCI Express x16 slot *SLI mode : x8 , x8 *Default(Single VGA) mode : x16, x1 - 2 x PCI Express x1 - 3 x PCI
LAN	nForce4 built-in Gbit MAC with external Marvell PHY : - NV ActiveArmor - NV Firewall - AI NET2 MARVELL PCI Gbit LAN controller : - AI NET2
Audio	Realtek ALC850, 8-channel CODEC Audio Sensing and Enumeration Technology Coaxial/Optical S/PDIF out ports on back I/O

The ASUS A8N-SLI Premium

The ASUS A8N-SLI Premium is a standard sized motherboard (12" x 9.6") that should have no issues fitting in any ATX compliant case. Everything is neatly laid out with no problem areas evident at first glance, but there are a few areas that need to be addressed which we'll discuss later on. Other than the motherboard, we received the usual assortment of SATA and rounded IDE cables, manuals and driver disks.

There are four ram slots that support Dual Channel and a maximum of 4GB. This is where we experienced a potential issue for those who tend to change ram modules often, as the ram slots are located in such a way that removal of ram will be near impossible without first removing the video card from the first PCI Express slot. While I would not go so far as to catagorize this as a problem, it is a nuisance. Also located in this area are the ATX 24-pin power, IDE1/IDE2 and the floppy connection.

Located between the CPU socket and rear I/O are some of the capacitors (mostly Rubycon), MOSFETs, ATX12V and the EZ Plug connections. It's interesting that ASUS went with heatsinks rather than their Stack Cool technology for cooling in this area, but personally, I find this more effective. The EZ Plug is required for stability with SLI configured and all you need is a spare MOLEX connection for it. We did find the area a bit tight with a graphics card and heatsink installed, but not impossible to work with. To help the system builder out, there is a warning LED that lights up in the event you've forgotten to plug in power to the EZ Plug connection.

To keep things chilly, ASUS uses an active cooling solution for the nForce 4 SLI chipset. The heatsink is held down by push pins which can easily be removed if you have an alternate cooler you'd like to use, though we recommend you only do so if you have a water cooler or an active air cooler. In this area, we have all our SATA connections split into two sets of four (eight total). Four connections are controlled by the NVRAID (black), and the other 4 by the Silicon Image 3114R (red). Both controllers support RAID0, 1, 0+1, JBOD, but the NVRAID also supports Native Command Queuing and the same flavours of RAID across SATA and PATA.

For expansion, the ASUS A8N-SLI Premium comes with two PCI Express x16, two PCI Express x1 and three PCI slots. Unlike the Deluxe version of the board, the Premium does not include the SLI EZ connector port on the mainboard, but rather, a PEG Link PCB board that connects to the graphics cards. ASUS also includes a support bracket which I feel is a requirement as the PCB board tends to move during transport. As we've covered in the past, the graphics operate at PCIe x16 with one card installed, and shifts to dual x8 when in SLI.

Editor's Note: While this board has not yet appeared on the ASUS product page as of this writing, the board does indeed differ from the A8N-SLI Deluxe. The Deluxe uses a daughtercard that bridges the SLI slots, while the Premium uses a chip. Other than that, the features are identical.

Rounding things out are your inputs and outputs. From left to right, we have; two PS/2, one Optical and Coaxial S/PDIF Outputs, one FireWire (1394), one parallel, four USB 2.0, two Gigabit Ethernet, and six audio connections. Additional connections are available with some PCI brackets in the package.

The BIOS

As usual with ASUS, the AMIBIOS is the center of the A8N-SLI Premium's board level tweak options. Everything is neatly arranged and pretty self explanitory. We figure most of you don't need a refresher on the basic items, so we'll go right into the juicy bits.

Under the advanced CPU Configuration, you have your processor information. You can adjust the Hyper Transport frequency (options are from 1x to 5x) which is tied into your CPU FSB as well as enabling or disabling the AMD Cool 'n' Quiet control. It is from here where you can also dive into your ram configuration.

While you can leave everything at Auto, those looking to squeeze the most out of their system will want to set everything manually. Your Max Memclock range from DDR200 to DDR600, and determined by ratios based on the assumption your FSB is 200MHz (for example, DDR400 is 1:1). You also have access to all your memory timings, where lower values will result in better performance.

Under the JumperFree Configuration screen, this is where you can access CPU specific overclocking options. Setting the Overclock Profile to AI N.O.S. will allow the board to use pre-set values maxing out at 10%. Setting the Overclock Profile to manual will allow the user to adjust things the old fashioned way.

The last thing of note is the SLI Configuration page where you can choose to enable or disable the EZ Plug warning. This screen also indicates whether the system is in single video card mode or SLI.

Software

There are some Windows based applications included with the board, but the ones of note are the AI Boost and AI Selector. The AI Boost is a Windows based overclocking, system monitoring tool and provided you have the board set to AI N.O.S., you can do some overclocking from a Windows interface.

The AI Selector was introduced with the A8N-SLI Premium and allows the user to set the board from single to SLI and back with a flip of the tab. A restart is required between mode changes, and once the system is back up and running, you're all set.

NVIDIA nTune is something we've covered before, but to summarize, it's an NVIDIA based application which can tweak a system either automatically or manually.

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