MCP-T, HyperTransport, and BIOS

MCP-T

As nForce2 boards begin to appear, you’ll notice manufacturers using one of two available Media & Communications Processors (MCP), depending on the target market. ASUS’ A7N8X Deluxe includes the more advanced MCP-T that features USB 2.0, ATA-133 and IEEE 1394 support. Additionally, it includes NVIDIA’s Audio Processing Unit and a pair of Ethernet MACs, making it easy to enable Internet Connection Sharing. ASUS uses two different Physical Layers (an Altima AC101LKQT and Realtek’s RTL8201BL) to enable both 10/100Mbps connections. Moreover, the Realtek RTL8801B PHY interfaces with the MCP-T to enable IEEE 1394 support at 100, 200, or 400Mbps. Despite the complexity of NVIDIA’s MCP-T, it doesn’t include Serial ATA support. So, ASUS integrated the Silicon Image Sil3112 controller, adding two S-ATA channels to the A7N8X.

NVIDIA's MCP-T

5.1 home theater setup via the nForce2 audio

The aforementioned Audio Processing Unit is one of the most distinguishing characteristics of the MCP-T. An nForce2 motherboard equipped with the MCP-T can output an encoded Dolby Digital signal to an external decoder, which separates the signal into 5.1 channels of discrete audio. NVIDIA’s reference design includes a SoundStorm ACR riser card featuring the connectors required for either digital or analog 5.1-channel output. However, the A7N8X comes equipped with analog and digital audio outputs, negating the need for NVIDIA’s ACR card.

Hyper Transport

Each chipset designer uses a different method for connecting the North and South Bridges. Intel uses its Hub Architecture – an 8-bit link between the two chips capable of transferring 266MB per second. VIA’s latest chipsets utilize 8x V-Link, an 8-bit bus running at 133MHz that is “quad-pumped,” transferring 533MB per second. NVIDIA was the first to use AMD’s HyperTransport with the original nForce and it capitalizes on the technology a second time with nForce2.

The SPP and MCP-T are linked using an 8-bit HyperTransport link operating at 200MHz, for a total data throughput of 800MB per second. The technology itself is scalable up to 12.8GB per second, but we probably won’t see bandwidth numbers like that unless AMD designs a specialized high-end server platform for its upcoming Opteron processor.

BIOS

The A7N8X features an Award BIOS with a host of adjustments catering to the enthusiast. Standard front side bus adjustments are available in 1MHz increments up to 211MHz, as well as multiplier adjustments that only become useful if you’ve unlocked your Athlon XP processor. NVIDIA recommends running the front side and memory busses synchronously, but if you’d prefer to overclock the memory bus, adjustments are available in the form of percentages. A Resulting Frequency field eliminates the guesswork, alerting you of the final memory frequency. Memory latencies can be altered down to 1 (we were unable to run CAS1 with our memory modules).

Processor, AGP, and DDR voltages can all be adjusted – Vcore voltages are available between 1.1V and 1.850V, AGP voltages range from 1.5-1.7V, and DDR voltages can be between 2.6 and 2.8V in .1V increments. AGP frequency can be set independently, anywhere between 50 and 100MHz, though we’d recommend sticking to the ‘Auto’ setting.

The nForce2 features several integrated subsystems like Ethernet, audio, and IEEE 1394. These systems can be independently turned off or on according to your needs. Finally, ASUS uses the Winbond W83791SD hardware-monitoring chip for the POST Reporting technology, which is adjustable in the BIOS.