The Input/Output Controller Hub (ICH) is is a highly integrated multi-functional I/O Controller Hub that employs the Intel Accelerated Hub Architecture (AHA) to make a direct connection from the graphics and memory subsystems to serve other chipset-enabled functions like the integrated AC97 controller, IDE controllers, dual USB ports, and PCI add-in cards. The following is the proper break down of the ICH's functional components:
Once more, note that there are two versions of the ICH - the 82801AA (ICH) and 82801AB (ICH0) hubs. The main differences are that the ICH has support for up to six PCI slots, U-ATA/66 and Alert-On-LAN, whereas the ICH0 doesn't have the last feature and only has support for four PCI slots and U-ATA/33. Here's a graphical view of it:
Besides being Intel's first chipset to sport integrated graphics, it is also AC'97 ready. This term means that the chipset has an interface catered to communicate with external audio and/or telephony codec chip(s) that can be mounted on the motherboard and the chipset refers to these codecs by means of the AC'97 link and uses CPU power to execute the sound and/or telephony features. Codecs are like written instructions to tell the system how to utilize it, e.g, an audio codec tells the system how to run and output audio but all processing brunt is tackled by the CPU.
These codecs are very cheap to include, hence an i810 based board can essentially have graphics, audio and modem functionality right on the motherboard, which brings about even cheaper systems based on Intel Celeron Processors, a market VIA and SIS completely missed to cash-in. CPU utilization shouldn't be much of a concern as a Celeron system can easily spare a few percent of processing power to support such all-round functionality in a typical Celeron-class system (targeting low to mid-range home and business users).
But providing the necessary codecs is up to the motherboard manufacturer's choice depending on the audience for which a particular board is targeted for. For example, the motherboard vendor can even forgo this route and integrate the actual sound or telephony chipsets on the board to produce better sound with no performance penalty on the CPU.
Having said that, there is yet one more choice and that is not to provide any of these functions and instead leave it completely optional by the way of an AMR slot that all i810 chipset boards support. AMR stands for Audio & Modem Riser card. It does just as what it says - provides Audio and Modem functionality on the cheap. It is similar to the motherboard vendor integrating the codecs onboard except that it is now on an AMR add-on card. An AMR card basically contains the codec chips and input/output connectors. The manufacturer can even combine the two methods, e.g. provide an audio codec on the motherboard but if you need modem and telephony functions, you can get an appropriate AMR card to handle only these functions at a very low cost; alternatively, you can get a dedicated PCI card to handle those functions more effectively. It's really giving more choices for the manufacturer and the user to expand their PC functionality at different cost points. At the time of publication, there aren't any commercial AMR cards yet and we guess manufacturers are waiting for the i810 boards to get more popular before offering AMR card solutions.
The i810 chipset does not come with an ISA bridge controller and is the first chipset to omit this, but it is an option that the manufacturer can choose to implement. Since it has now become an option and it is high time for ISA support to be discontinued, it's likely that most manufacturers will forgo supporting ISA add-on cards on their i810 boards.
There is now a new interface called a Low-Pin-Count (LPC) interface that is used to connect floppy drives and other port controllers which used to communicate via the old ISA-bus. Since ISA support is removed from the chipset (but can be included by manufacturer at additional cost), the LPC is a 4-bit, 33Mhz bus that is actually a simplified ISA bus to cater to these low bandwidth devices.
Lastly, the ICH has a Firmware Hub (FWH) interface, which is just a small 33Mhz bus to communicate with the FWH where the BIOS of both the system and integrated graphics are located.
If you're searching for the traditional big and bulky BIOS chip on an i810 board, you won't find one! In it's place is a tiny chip called the Firmware Hub (FWH) which may or may not be socketted (it was socketted on the DFI motherboard we've obtained for evaluation). It's size is similar to that of the new BIOS chips on the new Gigabyte-BX2000 motherboard. Even for the FWH, there are two variants of it! The i82802AB is a 4Mbit (512KB) part and the i82802AC is an 8Mbit part (1MB!). Currently most motherboards will use the 4Mbit parts, as it's more than enough for typical systems.
The FWH contains the BIOS for both the system and integrated graphics. The system BIOS has been greatly improved from the Award BIOS that we've been using for ages; for tweakers, there's plenty more fine-tuned options to choose from. Beside the BIOS, the FWH also contains the all-new, Random Number Generator (RNG). Intel claims it is used for greater security. This is a snippet from the Data-sheets:
"Intel will provide a Windows driver to give third party software access to our RNG for use as a security feature. Also provided will be a device driver developer kit (DDK) for operating system vendors who wish to design security drivers for their platform."
Well, one thing is for sure - RNG really works! How do I know? When I booted up the PC using the DFI i810 motherboard, during the HDD auto-detection, it will auto-detect your HDD and assign a unique number. Since I had two HDDs, I found two very different numbers assigned to them. When I restated the PC, the assigned IDs were radically different for both. I've since re-booted numerous times, never seeing the same pair of numbers again. Intel has featured this RNG function in hardware because hardware generated numbers have a far less chance to repeat themselves in a certain given period and the fact that the numbers generated are a bigger string than software generated numbers - as claimed by Intel. There are more security related features but if you need to know more and are comfortable getting technical, do read the data sheets.
At this juncture, we've concluded how the i810 platform architecture works, so here's a photo of how an i810 boad would look like and the location of the many new components we've discussed by using a DFI PW65-D (i810 board) for illustration: -