Integrated 3D Graphics
Intel is trying to make a point and wants to prove that i815 is only for the 'value' segment and thus no competitor to the wonderful RDRAM-chipsets i820/i840 by integrating a 3D graphics solution into Solano. However, different to the i810 chipset, which forces you to use its integrated graphics, i815 turns off its internal 3D graphics as soon as you plug an AGP-card into the system.
Most of us won't care much about this added 'value segment aliby' feature, but it might come in handy for the OEMs that try and produce cheap Pentium III platforms. We, the performance consumers, will have to pay for these integrated graphics, regardless if we want it or not.
ICH/ICH2 Goodies
The other goodies are all the stuff we're used to and some more. i815 offers AGP4x support and it's using the 'Intel Hub Architecture' with its advantage of a data path of 266 MB/s bandwidth between 'North' and 'South' bridge vs. the usual connection via the PCI -bus, which is limited to 133 MB/s.
Depending if Solano comes with the well-known 'ICH' 'I/O Controller Hub' or with 'ICH2' you get even more features. Solano with ICH offers ATA66-support, AC97-support, full ACPI-support (for the ones who care) and one USB hub. ICH2 adds ATA100-support, another USB-hub, a six channel AC97-codec and semi-integrated LAN as long as you add a chip called 'PHY' to it.
