Intel i845G Overview
The Intel i845G chipset extends the Intel Pentium 4 Processor platform to the next level. The processor interface supports 400MHz and 533MHz Quad-Data Rate (QDR) Front Side Bus operations. The i845G couples PC133 SDRAM support (for value end) and PC1600/2100 DDR SDRAM (for Mainstream). The most significant change to the i845 platform is the incorporation of Intel Extreme Graphics controller, built directly into the i845G Northbridge. The graphics card technology is built once again on Intel's Dynamic Video Memory Technology (DVMT) system. This allows the Video card to automatically select its own required memory for 2D and 3D operations. On initial boot the video system uses only 1MB of system memory for video operations. When required, the video card can increase its memory requirements up to a total of 48MB. This allows for maximum expansion for value graphics.
Finally, after three generations of chipsets using the same ICH2 controller, Intel has updated it and named it ICH4. ICH4 contains 90% of its original ICH2 specifications, however, they have been updated. AC'97 has been updated to rev 2.2 for 6ch audio. USB ports have increased from 4 to 6 ports spanning 3 controllers (similar to VIA's design). Not only are there 6 ports, but they are high-speed USB 2.0 controller ports. That's right, the first commercially integrated USB 2.0 on a Southbridge. Some people might be wondering why is there a ICH2 and ICH4 but no ICH3. Well let me tell you there is and was an ICH3; this was used in Mobile i815 notebooks. Just a bit of trivia.