Software decoders requires quite little CPU power and can save you a PCI slot, so why go for a hardware decoder? A hardware decoder generally is for people with slower computers. If you have anything less than an equivalent of a Celeron 300a processor, then you should seriously consider either getting a CPU upgrade (which will improve general system performance - esp. 3D games) or go for a hardware decoder card (if you don't really care about playing 3D games). A hardware decoder card also has several advantages over software DVD decoders :
Advantages of using hardware decoders :
Saves your CPU for other uses
Allow external TV output (both composite and s-video) and better quality than software decoder + TV-out card
Allow S/PDIF AC3 connection to external decoder
No dependencies on graphics card hardware overlay layers
If your card is a popular type (eg. Hollywood Plus), disabling Macrovision (allow you to connect to a VCR to record DVDs, or to bypass to the TV if your TV does not have S-Video/composite inputs) may be easy
Disadvantages of using hardware decoders :
Poorer quality than software decoders in "monitor" view, due to use of VGA-Decoder plug-thru cable
Many modern graphics card also do have TV-output (Asus v3400TNT/TV - both composite and s-video) and can be used with software decoders
Newer range of sound cards also have S/PDIF output (New SB-Live range - AC3 to external decoder) and can be used with software decoders
Modern 450Mhz+ CPUs are more than enough for software decoding (usually only 20-30% of utilization is needed when playing DVDs)
DVD Region settings hard to change (unless you have a popular card like the Hollywood Plus)
Can only use the player supplied with the card - cannot use PowerDVD/WinDVD, which have more features and better support for the latest DVD titles
WHICH HARDWARE DECODER IS BEST ?
Actually, most decoders offer pretty much the same, in terms of features and quality. But certain decoder have better support than others. Region-changing utilities (such as the excellent DVD Remote Selector) for hardware decoders only work with popular decoder cards. So what is the most "popular" card ?
1. Sigma-Designs RealMagic Hollywood+ 2. Creative DXR-3
(both use the same decoding chip and their drivers are inter-changeable)
