815 Features

BX versus 815: A Quick Comparison
	440BX	815/815E
North Bridge	82443BX	82815
Front side bus	66/100MHz	66/100/133MHz
Memory bus speeds	66/100MHz	66/100/133MHz
Peak bandwidth	800MB/sec	1.0GB/sec
Total Bandwidth	2.26GB/sec	3.13GB/sec
AGP 2X/4X	Yes/No	Yes/Yes
Max DIMMs	4	3
Max Memory	1GB	512MB

A New Architecture

Like the other 800 series chipsets, 815 is based on Intel's new Accelerated Hub Architecture. Unlike traditional chipsets such as BX and even VIA's newer KX/KT133 that use traditional North and South Bridges to "speak" with the components inside your PC, Intel's hub architecture uses a memory controller hub (or in the case of 810/815, graphics memory controller hub as both chips feature integrated graphics) and an I/O controller hub.

The MCH and ICH are linked together by a 133MHz bus that transfers data on both the rising and falling edges of each clock cycle, effectively yielding 266MHz; traditional chipsets link the North and South Bridge with the PCI bus at 133MHz.

The I/O Hub

All 800 series chipsets use the same ICH. Notable features supported by the ICH are ATA/66, 2 USB ports, and AC97 for onboard sound. The 800 series chipsets with the "E" designation (810E, 815E, and 820E) come with the newer ICH2 that adds two USB controllers, (for up to four USB ports) ATA/100 support, AC97 audio, and integrated LAN capability with the new communications and network riser (CNR) slot.

The CNR slot

CNR is the successor to last year's AMR slot, with CNR offering the traditional audio functions of AMR with the added capability of networking. We still haven't seen a single AMR card on the market, but perhaps the added capability of networking may convince a manufacturer to adopt a CNR product.

The GMCH

The most notable portion of the 815 chipset however is the graphics memory controller hub. (GMCH) Since 815 is a low-end offering, it offers complete SDRAM support.

Front side bus speeds supported include 66, 100, and 133MHz, with memory bus speeds of 100 and 133MHz available to choose from. That's right, just like VIA's newer 133MHz chipsets, with 815 you can adjust the memory bus independent of the front side bus.

This is an excellent feature for anyone who would like to run their memory bus at 133MHz while the front side bus remains at 100MHz, or vice versa.