Chipset features compared
Forgive the extremely wide formatting here, but I'm trying to fit all of the relevant chipsets into our comparison table, so you can see how these products differ. I've omitted less interesting chipsets like the 845GL and 865P in order to save some space.

Intel 845PE Intel 845GE Intel 850E Intel E7205 Intel 865PE Intel 865G Intel 875P SiS 648 SiS 655 SiS R658 VIA P4X400
Max. bus speed 533MHz 533MHz 533MHz 533MHz 800MHz 800MHz 800MHz 533MHz 533MHz 533MHz 533MHz
Memory type DDR DDR RDRAM DDR DDR DDR DDR DDR DDR RDRAM DDR
Max. effective memory clock speed 333MHz 333MHz 1066MHz 266MHz 400MHz 400MHz 400MHz 333MHz
(400MHz unofficial)		 333MHz
(400MHz unofficial)		 1066MHz 333MHz
(400MHz unofficial)
Memory bus width 64 bits 64 bits 2 x 16 bits 2 x 64 bits 2 x 64 bits 2 x 64 bits 2 x 64 bits 64 bits 2 x 64 bits 2 x 16 bits 64 bits
Peak theoretical memory bandwidth 2.7GB/s 2.7GB/s 4.2GB/s 4.2GB/s 6.4GB/s 6.4GB/s 6.4GB/s 2.7GB/s
(3.2GB/s)		 5.4GB/s
(6.4GB/s)		 4.2GB/s 2.7GB/s
(3.2GB/s)
Maximum addressable RAM 2GB 2GB 2GB 4GB 4GB 4GB 4GB 3GB 4GB 4GB 3GB
Max. AGP mode 4X 4X 4X 8X 8X 8X 8X 8X 8X 8X 8X
North/south bridge interconnect Accelerated Hub Accelerated Hub Accelerated Hub Accelerated Hub Accelerated Hub Accelerated Hub Accelerated Hub MuTIOL MuTIOL MuTIOL V-Link
Interconnect clock speed 266MHz 266MHz 266MHz 266MHz 266MHz 266MHz 266MHz 533MHz 533MHz 533MHz 533MHz
Interconnect bus width 8 bits 8 bits 8 bits 8 bits 8 bits 8 bits 8 bits 16 bits 16 bits 16 bits 8 bits
Peak theoretical interconnect bandwidth 266MB/s 266MB/s 266MB/s 266MB/s 266MB/s 266MB/s 266MB/s 1.06GB/s 1.06GB/s 1.06GB/s 533MB/s
Disk interface support up to... ATA/100 ATA/100 ATA/100 ATA/100, Serial ATA 150 ATA/100, Serial ATA 150 ATA/100, Serial ATA 150 ATA/100, Serial ATA 150 ATA/133 ATA/133 ATA/133 ATA/133
USB mode support 2.0 2.0 1.1 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0
USB controllers/ports 3/6 3/6 2/4 4/8 4/8 4/8 4/8 3/6 3/6 3/6 3/6
IEEE 1394 controllers/ports 0/0 0/0 0/0 0/0 0/0 0/0 0/0 2/6 2/6 2/6 0/0
AC97 audio channels 6 6 6 6 6 6 6 6 6 6 6
Network interfaces 10/100Mbps Ethernet 10/100Mbps Ethernet 10/100Mbps Ethernet 10/100Mbps Ethernet CSA CSA CSA 10/100Mbps Ethernet
1/10Mbps HPNA		 10/100Mbps Ethernet
1/10Mbps HPNA		 10/100Mbps Ethernet
1/10Mbps HPNA		 10/100Mbps Ethernet

The 865 family chipsets lead on the technology front, with a couple of possible exceptions. For one, they lack Firewire support, which SiS chipsets have. Also, chipsets from SiS, VIA, and NVIDIA support the ATA/133 disk I/O mode. Like many drive makers, Intel elected to skip this step and go straight to Serial ATA. Finally and perhaps most notably, even the new 865 and 875 chipsets have a relatively pokey 266MB/s peak transfer rate between north and south bridge chips. The 865 could fill that channel to overflowing by bursting data from cache on a pair of Serial ATA drives in RAID 0—and nothing more. CSA's relocation of network I/O from the ICH to the MCH will help some, but Intel is still behind the curve on chipset interconnect bandwidth for some reason. This 266MB/s link is a built-in bottleneck—in theory, if not in practice.