SPP

Unreal Tournament 2003 shot

Here's another UT shot

With nForce2, the majority of the new action takes place in the North Bridge of the chipset; traditionally NVIDIA has referred to this as the integrated graphics processor IGP). However, since nForce will launch with variants both with and without integrated video, the North Bridge that lacks the integrated graphics core is known as the system platform processor (SPP), while the chip with integrated graphics is still known as the IGP. Lets start off with the SPP first.

The SPP

You can’t discuss the North Bridge of the nForce chipset without first discussing its TwinBank memory architecture. If you recall the original nForce chipset, TwinkBank offered up to 4.2GB/second of bandwidth. Each of its dual memory controllers had its own 64-bit bus to the rest of the system. As a result, the CPU and GPU (if present) could access memory simultaneously, or one of the components could have all of TwinBank’s bandwidth to itself. With DDR266 memory, this configuration offered up to 4.2GB/second of bandwidth. To this day that is still more bandwidth than any of the latest DDR333 chipsets currently available for Athlon. So what does NVIDIA do with nForce2 to top this figure?

Not only does nForce2 support DDR333 memory technology, nForce will also fully support upcoming DDR400 memory. With each DDR400 module providing 3.2GB/second of bandwidth, that gives nForce2 up to 6.4GB/second of memory bandwidth! That’s 58% more bandwidth than any of today’s fastest chipsets currently available for the Athlon platform, and twice the bandwidth of any upcoming DDR400 chipset.

If you recall the implementation of the original nForce chipset, the dual memory controllers could only support up to five banks of memory. If the third DIMM slot was populated with a double-sided memory module, the nForce chipset would run in compatibility mode, severely crimping overall system performance. As a result, the third DIMM slot was essentially useless to power users unless they were able to come across a single-sided DDR memory module.

NVIDIA has addressed this issue with nForce2 by adding a third address line to the controller so all three DIMM slots can operate at the same speed. Like the original nForce chipset, the controller will only run as fast as the slowest memory module, so if you want DDR400 performance you’re going to have to populate all three DIMMs with DDR400 memory.

Besides adding support for new memory types, NVIDIA has also doubled the maximum amount of memory from 1.5GB to 3GB. Each slot is capable of handling 1GB DIMMs.