The SiS630S video is a 2D/3D, 128-bit video accelerator based on the SiS300 design. In addition to solid DirectX support, the card supports OpenGL, albeit very slowly, hardware motion compensation for excellent DVD playback, an integrated TMDS for digital flat panels, 3D glasses, and resolutions up to 1920x1200@80Hz in 16-bit color on an analog display. Overall, the video feature set is basic, though the DVD playback is top notch and uses very little CPU power.
One interesting feature is that, with the addition of a SiS301 external video chip, you can add a second AGP video output while still using the integrated chipset video. You can also add a video card to the external AGP 4x slot, though unless it uses the aforementioned SiS301 video chip, the integrated video will be disabled. Neither Intel nor VIA's integrated video gives you the ability to do dual-head using the internal video.
The Southbridge is the least sexy component of any system, but it is also where the features you interface with lie. The SiS630S' internal southbridge features ATA/100 support, two USB controllers for up to five USB ports, integrated 10/100 Ethernet, AC'97 AMR support, low-power modes, and wake-on-LAN and modem. It also has an integrated audio controller, which can connect to an external codec to deliver up to six channels of audio. This is a full-featured southbridge that is the equal of Intel's best, on a feature basis.
Video performance with the SiS630S chipset is poor compared to aftermarket video cards, but excellent compared to what Intel and VIA are currently integrating. You can expect DirectX speed on the order of a TNT1, which is not enough for a serious gamer but will let you get in the door on almost any game. The performance does fall down though in OpenGL. SiS' OpenGL drivers need a lot of work, so Quake III Arena players on a tight budget will want to skip this chipset.
Overall system performance with an external AGP card is quite good. It does not run as quickly as an i815E system, but with PC133 memory and 133MHz FSB support, the chipset does as well or better than VIA's PM133 chipset. The SiS630S chipset provides an inexpensive, full-features alternative to Intel's i815E chipset.