VIA's P4X266
Like the Intel 845, VIA's P4X266 supports PC133 SDRAM. In fact, feature-wise, the PX266 seems to do pretty much everything the 845 chipset can do, plus one big addition: the P4X266 supports DDR memory right now. Up to 4GB of it, in fact. That gives the P4X266 a theoretical peak of 2.1GB/s of memory bandwidth. Combined with DDR SDRAM's other advantages—lower prices, lower latencies—the P4X266 may give Intel's high-end 850 chipset a run for its money.

Let's review a few of the similarities between the P4X266 and Intel's P4 chipsets, because the similarities are striking. Both have the requisite P4 bus, of course. Both have AGP 4X, and both have dedicated 266MB/s interconnects between north and south bridge chips. Both hang the PCI bus off of the south bridge, and they support the same I/O standards: ATA-100, USB, and AC'97. Both use Intel's LPC interface to talk to legacy devices like keyboards, so neither chipset natively supports ISA slots. Motherboard chipsets are complex beasts nowadays, yet these two companies have achieved feature-for-feature parity.

The P4X266 is actually very similar to VIA's KT266/KT266A chipset for the Athlon. In fact, beyond the CPU bus interface, the P4X266 and KT266A are probably almost identical. Like the 845/850, the KT266A and P4X266 share the same south bridge chip. In this case, that's VIA's 8233 chip.

VIA does have one more trick up its sleeve for the P4X266: due out before long is the P4M266, essentially the same product, but with an integrated S3 Savage4 graphics controller. For low-cost OEM solutions, that could make VIA's P4 chipset quite popular.

A P4X266 chipset block diagram

The P4X266 north bridge chip needs only a small passive heat sink

VIA's VT8233 south bridge chip