On the cooling front, the stock heatsink and fan covers the GPU and works much like any other fan by drawing air in and circulating it around. Granted, the air it pulls is from within the case, so don't expect any cutting edge cooling performance, but the setup is quiet and the card itself does not generate that much heat.

As most HTPCs are not built with raw power in mind, quiet performance as well as power efficiency are high priorities. The AIW HD fan does make a fairly loud whir at start up, but goes near silent once the system starts up. The AIW HD does not require additional power either, cutting on cable clutter around the card as well as using less power than a high performance card.

The Theater 650 chip is an audio/video decoder, MPEG-2, WMV9 and H.264 encoder. The chip features a 12-bit video decoder, which offers more precise video capture and outputs more realistic colours.

Enhanced DVD Up-scaling - Watch standard definition video in near HD quality with DVD up-scaling. ATI All-in-Wonder™ HD uses post processing to enhance standard and low resolution videos and movies for your HD display.

Unified Video Decoder – Enjoy the latest Blu-ray movies and other HD content with a dedicated hardware video decoder1. The UVD offloads the intensive process of HD video decoding and playback from the CPU to the GPU while improving visual quality. 

The Theater 650 supports a 3D motion adaptive comb filter, which supports both Sequential Color with Memory (SECAM), NTSC and PAL standards. The 3D comb filter is used on low motion scenes. Examples of these are still pictures, slow moving video or static items like the broadcaster's logo. 

  
No comb filter (left), Theater 650 3D Comb Filter (right)

Usually the 2D filter was used to separate the luminance and chrominance components of the TV signal. This can cause color artifacts around the edges or a dot-crawl effect. The 3D filter analyzes 5 lines of video in the current frame, and also scans ahead 1 frame to analyze the video to see if the picture changes.

A 5-line 2D comb filter is used on the high motion video feeds. A 5-line filter ensures that every pixel is separated with a high degree of accuracy. By reading ahead 5-lines before the video is processed, the comb filter can detect similarities in the lines and determine how to separate the signal in the most efficient manner. Another image quality enhancement is noise reduction. Noise or snow can be seen in lower quality signals, or video streams. The Theater 650 contains advanced dedicated algorithms which search for a variety of noise in the signal and cancels it out. This is also done on-chip, to reduce CPU utilization.

Automatic gain control is a system in which the video stream is smoothed of any major fluctuations in signal strength or in brightness or intensity of the light displayed. These differences are often evident on channel changes, where the screen will become extremely bright. The Theater 550 Pro used a single staged gain control, but the 650 Pro uses a multistage and multispeed control.