In June 2003, ATI launched their long awaited Pentium 4 chipset, the RADEON 9100 IGP. Codenamed RS300, the RADEON 9100 IGP was aimed to bring performance to the value market. Instead of competing with their archrival NVIDIA in the AMD camp, ATI is exploring the Intel route. However, one cannot but compare ATI with NVIDIA in this situation too. Both companies have established themselves as the key players in the consumer 3D graphics processor market. When both companies decided to begin developing IGP chipsets, many could foresee new levels set in integrated graphics which has so far been marred by severely crippled performance.
In terms of integrated graphics for the Intel platform, the only passable chip at the time was Intel's own 865G. ATI was banking on the success of their RADEON series of VPUs to make an inroad. Thus, the RADEON 9100 IGP was introduced as the direct competitor to the Intel 865G for Pentium 4 and Celeron processors on socket 478.
ATI's Trump Card
The 9100 IGP boasted a built-in RADEON 9200 VPU with an impressive feature list. It was the first P4 chipset to have hardware pixel shader 1.4 and DirectX 8.1 support and was capable of 4x FSAA (Full Screen Anti-Aliasing) and 16x AF (Anisotropic Filtering). It also boasted TV-Out support and a feature called SURROUNDVIEW, which enables support for three monitors by combining an external AGP card with the IGP. The Intel 865G's Extreme Graphics 2 core however, was a DirectX 7 part with no pixel shader or FSAA support and it wasn't able to live up to its 'Extreme' moniker in real world performance.
An inherent weakness with integrated graphics chipsets is the use of system resources. They have to share onboard RAM, relatively many times slower than dedicated memory available to standalone graphics cards. Memory bandwidth in today's graphics accelerators exceed 30GB/s. Comparatively, the dual channel DDR-400 controller of the 9100 IGP has a peak bandwidth of only 6.4GB/s. You can see how this will impact performance throughput. In an attempt to alleviate this bottleneck, ATI has incorporated memory compression technology into the chipset. The 9100 IGP is capable of 2:1 data compression along the memory bus, which should definitely help graphics bandwidth loads.
What Went Wrong
At first ATI seems to be positioned in a sure win scenario. However, their inexperience in engineering and developing mainboard chipsets showed. The 9100 IGP suffered from poor system performance, which is ironic since the problems plaguing IGP chipsets have always been graphics performance. It seems ATI placed too much emphasis on optimizing the graphics core at the expense of total system efficiency. The 9100 IGP memory controller had compatibility issues with many types of RAM and problems also arose with inferior AGP 4x/8x implementation. Without its onboard graphics to back it up, the chipset started to fall behind in other areas.
Nine months later, in May 2004, ATI introduced the enhanced version of the RADEON 9100 IGP, the RS350. This chipset was duly christened as the RADEON 9100 PRO IGP. Looking at the graphics capabilities, it seems that ATI is confident of their superiority in this area as the graphics core has not changed. It is still powered by the RADEON 9200 VPU @ 300MHz. So what is new in this iteration of the chipset? ATI has tried to rectify the shortcomings of the original 9100 IGP, mainly being the lackluster performance and compatibility of the memory controller and external AGP interface. The new chipset actually comes in two flavors, the RS350 and the RC350. Feature wise, they are identical except that the RS350 sports a 128-bit dual-channel memory controller (128-bits split into two 64-bit channels), while the RC350 only supports a single 64-bit channel.