The nForce 680i SLI Chipset and Motherboard
Now that we've covered the high-level features of the nForce 680i SLI, we can delve a little deeper and explain what really makes the chipset tick. NVIDIA claims they worked closely with intel during the design phase of the 680i SLI to expose as much performance as possible from the Core 2 Duo and Core 2 Quad processors.
The 680i SLI is a two-chip solution comprised of the 680i SLI SPP and 680i SLI MCP. Both chips are manufactured at 90nm, and are designed to have plenty of overclocking headroom. One of the major parts of the chipset that's largely responsible for its high performance is a newly designed Dual-DDR memory controller that features DASP 4.0 with QuickSync. NVIDIA's Dynamic Adaptive Speculative Prefech (DASP) 4.0 has been tuned for the new pre-fetch patterns inherent to Intel's SmartCache technology at work in the Core microarchitecture. And QuickSync is a mechanism designed to bypass asynchronous logic to speed memory transfers between the CPU and system memory.
The block diagram above, gives a good visual representation of what features are incorporated in the new SPP and MCP chips. We should also note that the SPP and MCH communicate with each other over an x8 HyperTransport link operating at 1GHz.
NVIDIA is moving in a new direction with the nForce 680i SLI chipset. When the company launched the nForce 590 SLI for the AMD platform, NVIDIA designed a reference motherboard that exploited all of the features inherent to the chipset and their partner, Foxconn released a motherboard based on the design. With the nForce 680i SLI, however, NVIDIA is taking this model one step further. In addition to designing and building nForce 680i SLI motherboards, NVIDIA is seeding partners with boards which will all be released under their respective brand names. A handful of partners will be designing their own 680i SLI motherboards, but partners like EVGA, XFX, Foxconn, and BFG will be releasing the motherboard you see pictured here.
The motherboard that we tested came by way of EVGA. Along with the motherboard itself, EVGA included a complete user's manual, a driver / utility CD, RAID drivers on a floppy disk, and a wide array of cables and adapters. There were also rounded floppy and IDE cables in the box, six SATA cables, three 4-pin Molex-to-Dual SATA power adapters, USB, Serial, and Firewire case brackets, an SLI bridge connector, a custom IO shield, and an optional fan that can be mounted to the SPP heatsink for better cooling performance.
The EVGA nForce 680i motherboard itself features a 6-phase VRM, and the SPP, MCP and VRM are all passively cooled with aluminum heatsinks that make use of heat-pipes. With the optional fan installed, cooling is no longer passive, obviously, but this fan is only recommended for use while overclocking. For normal activities, the fan isn't a necessity.
In general, the motherboard has a very good layout. It was designed to be used with a pair of double-wide graphics cards installed in SLI mode, so connector placement is good and won't interfere with the graphics cards. The motherboard's expansion slots are also configured in such a way that there is more space between a pair of graphics cards when installed. In total there are three PCI Express x16 slots (X16, X8, X16), two PCI Express x1 slots, and two standard PCI slots. Why three x16 slots you ask? To support a third graphics card for physics or GPGPU duties, of course. More on that in our GeForce 8800 coverage.
All of the motherboard's headers are clearly labeled, which makes installation relatively easy. The board also features handy power and reset micro-switches and an LED POST code error reporter. Its single Floppy and IDE connectors are located along the front edge of the board, just above two of the six SATA ports. The other four SATA ports are situated just behind the IDE connector, in front of the four DIMM slots.
The I/O backplane houses PS/2 mouse and serial ports, a single Firewire port, six USB 2.0 ports, analog and digital audio inputs and outputs, and a pair of RJ45 LAN jacks. Audio duties on the board are handled by a Realtek HD ALC855 codec, and dual-Gigabit LAN comes by way of a pair of Marvell transceivers.