Intel 440MX - 440BX's Little Brother
I2C/SMBus is supported by all current chipsets. Many notebook vendors currently use the i440BX chipset for their notebooks. The regular readers of Tom's Hardware Guide know this chipset from desktop motherboards. But there is also a virtually unknown chipset the so-called i440MX.
It is very important for a notebook designer to get everything as small as possible. A BX design needs real estate for two chips. The i440BX north bridge and the PIIX south bridge. The i440MX chipset includes the north and south bridge in just one chip.
When you take a closer look at the picture above, you will notice that there is only 1 EIDE controller. There is no need for a second EIDE channel in a notebook with only 2 EIDE devices, the HDD and the CD/DVD drive. In the process of stripping down features, Intel engineers also removed the AGP port. A few features were actually added as well. The AC'97 link was introduced into the mobile chipsets first. With AC'97 it is possible to provide a cost effective audio solution and save space.
New chipsets like the mobile i815EM have the advantage of an integrated VGA controller that can use the main memory as its frame buffer. All these special chipset features might look strange from the desktop point of view, but from the notebook perspective it paints a different picture.