Apparently, in spite of last week’s suggestions Intel did not add AGP support into its i915-series (Grantsdale) chipsets, but some makers of mainboards had found a way to implement AGP via typical PCI bus, AnandTech web-site reported.

Last week a number of mainboards based on the i915P core-logic with PEG x16 and AGP slots for graphics cards were spotted at Computex Taipei 2004 trade-show. Since Intel’s upcoming chipset was not originally set to support AGP slot, it was a big surprise for hardware community that a number of platform producers implemented the slot that will be phased-out later this year on their new mainboards. However, it appears that AGP on the i915P and SiS656-based mainboards is not native, but is incorporated using typical PCI slots.

Mainboard makers use two PCI slots from ICH6 to “emulate” the presence of AGP. Since two PCI slots only provide 133MB/s bandwidth, performance when using AGP graphics cards drops tremendously. Typical AGP 8x pump up to 2.1GB/s and also sports numerous speed-boosting technologies, such as sideband addressing.

Manufacturers of mainboards believe that additional flexibility with AGP and PCI Express graphics cards is an advantage for consumers, which is doubtful. The majority of end-users acquiring PCI Express-enabled platforms would prefer modern graphics cards and would not sacrifice performance of their PCs. Customers who are not looking for the latest technology are likely to get a previous generation platform that costs much less compared to the cutting-edge flavour of technology.