nVidia, a traditional video chip - and more recently motherboard chipsets - manufacturer, has launched two new models of socket 462 motherboard chips, that is, motherboards for AMD processors (such as Duron and Athlon XP). Those two new chips are called nForce 2 400 and nForce 2 400 Ultra.

The innovation in those two chips is that they accept the new 400 MHz bus used by the Athlon XP 3200+ model. Besides, they support the AGP 8x bus and have six USB 2.0 ports. The 400 Ultra model replaces the nForce 2 SPP chipset, a very popular chip among enthusiastic users and gamemaniacs, which due to its 333 MHz external bus does not accept the 3200+ CPU.

The difference between those two new models is the DDR Dual Channel feature. The Ultra model, as well as the nForce 2 SPP, is capable of accessing the 128-bit memory and not the 64-bit one, as it happens with chipsets without this feature, doubling the transfer rate in the access to the RAM memory. If you use two DDR400/PC3200 memory modules, the transfer rate increases from 3.200 MB/s to 6.400 MB/s. At least in theory. As for the nForce 2 400 model such feature is not available, for this is a chipset for the low-end market, but it does accept the new 400 MHz bus.

The good news is that nVidia sold several nForce 2 400 Ultra chipsets to motherboard manufacturers as if they were nForce 2 SPP ones. To be even more precise, starting from nForce 2 SPP C1 stepping it is, indeed, the new nForce 2 400 Ultra. In other words, if you have a motherboard based on the nForce 2 SPP it is possible that the chipset on you motherboard is, in reality, the new nForce 2 400 Ultra, accepting the Athlon XP 3200+, and that means you do not need to change motherboards in case you want to install Athlon XP CPUs with 400 MHz Front Side Bus (however, you will have to make a BIOS upgrade so that your motherboard can recognize that new processor correctly and can enable the 400 MHz bus configuration in the board setup). Such is the case with the ASUS A7N8X De Luxe motherboard, for instance.

To know if you have been gifted" with an nForce 2 400 Ultra, all you have to do is to install the latest version of the nForce 2 dirver, available at http://www.nvidia.com/content/drivers/drivers.asp. After installing the driver, see on Device Manager (System icon in Control Panel; on Windows XP you have to click on Hardware tab and then on Device Manager box), under the System devices tab how the motherboard chipset is recognized. In you read "NVIDIA nForce 2 Ultra 400 Memory Controller" then congratulations! Your motherboard is already fitted with that new chip.

Figure 1: nForce 2 SPP is recognized as an nForce 2 400 Ultra in ASUS A7N8X De Luxe.