nForce2: Overclocking Made Easy
NVIDIA also took power-hungry users into consideration - the integrated clock synthesizer should allow you to overclock the three most important elements (CPU, system memory, AGP) independently from one another. However, it will depend heavily on the motherboard makers as to how this will work in practice and if this sort of functionality will be integrated in the BIOS.
It also remains to be seen if the asynchronous operation of all components is worth it. A direct, one-to-one clock correspondence (e.g., 133 MHz FSB, 133 MHz RAM) is certainly the best choice. Pseudosynchronous relationships (e.g., 133 MHz FSB, 166 MHz RAM) result in significantly longer latencies. We will be investigating how asynchronous clock modes (e.g., 145 MHz FSB, 166 MHz RAM) influence performance as soon as we get a motherboard that allows this sort of tuning. However, features such as the dual memory controller or the isochronous HyperTransport protocol might be able to make up for this possible disadvantage.
Music Is In The Air: The Audio Processing Unit (APU)
NVIDIA defines the term "Audio Processing Unit" as the following: a sound unit with hardware acceleration for 256 voices, 64 of which are 3D voices, as well as an extensive 3D sound logic based on multiple signal processors, support for DirectX 8 and output via Dolby Digital 5.1. The signal must be encoded in the hardware, of course.
The APU itself consists of four parts, which NVIDIA calls "processors":
- Setup Engine
This determines the parameters for the other three processors. The Setup Engine is also responsible for memory management, mapping and DMA resources.
- Voice Processor
This contains a DSP (Digital Signal Processor), which has several functions for processing the voices and mixing the results in a buffer.
- Global Processor
This unit consists of a programmable DSP. It adds other effects, including programmable effects, produces the audio stream, and outputs to the operating system.
- Dolby Interactive Content Encoder
The name is pretty self-explanatory. Again, this involves a programmable DSP, which encodes Dolby Digital 5.1 and outputs the datastream to the SPDIF-out. This enables a complex 3D audio stream to be sent over a single digital cable and transmitted via 5+1 loudspeakers (five plus subwoofer).
You can read about further details in the article NVIDIA nForces Success In New Market: APU - The Audio Processing Unit .