Packaging/Motherboards

478-pin CPUs

To ease the transition from today's Socket 423 Willamette Pentium 4's to the upcoming Socket 478 Northwood Pentium 4's; Intel has begun the production of Willamette CPUs utilizing the new 478-pin interface. Already we've seen 478-pin Willamette CPUs as low as 1.5GHz, and quite a few motherboards based on Intel's upcoming 845 chipset that utilize the new socket.

Socket 423 on the left Socket 478 on the right

The underside of both chips

As you can see in the pictures, the new 478-pin processors are considerably smaller than their 423-pin predecessors. Intel has implemented this new microPGA package to cut manufacturing costs. With the new package, all excess packaging around the P4 core has been removed; leaving just enough space for the integrated heat spreader that covers the P4 core. With a smaller surface area to work with, pin density on the underside of the chip has been dramatically increased.

Fortunately the pins themselves are pretty sturdy. Bending a pin on one of these chips is definitely more difficult than it's been in the past, but certainly possible. We're still afraid of bending a pin on our current P4s, so we can only imagine how intimidating it would be to repair a bent pin on one of the newer 478-pin P4s. Definitely be sure to work slowly and carefully with these new chips!

For support of existing Socket 423 motherboards, 2.0GHz Pentium 4 processors will also be available in 423-pin configuration, although we're unsure how long production will last. 2.0GHz is the final release for this socket, all Pentium 4 releases from now on will solely be available with 478-pins. For this reason, we recommend that anyone interested in buying a Pentium 4 processor purchase the 478-pin CPU, rather than the 423-pin chip. While the 423-pin CPUs scale from 1.3GHz-2.0GHz and only support one core (Willamette), the 478-pin chips scale from 1.5GHz-2.0GHz+ and support both today's Willamette CPUs as well as the next generation Northwood Pentium 4s. Essentially, by going the Socket 478 route, you'll get a platform with a much longer lifetime than previous motherboards. Rather than upgrading the motherboard and CPU, you'll just need to swap out the CPU; this saves you a nice chunk of change you can then apply to a faster graphics card, or additional system memory.

The motherboards

Just which motherboards support this new interface? Right now, there really aren't many Socket 478 motherboards on the market. ABIT's TH7II-RAID is now beginning to hit US shores (with prices starting at over $180), while Intel's D850MD has recently debuted on Pricewatch. With its micro-ATX form factor the D850MD only offers three PCI slots and limited BIOS options, so we doubt many of you will consider it an ideal solution (not to mention the $174 price it's currently going for).

ABIT's TH7II-RAID

The Intel D850MD

In contrast we've seen quite a few Socket 478 845 motherboards, and even one based on the P4X266 chipset (which we can't tell you about just yet). We know that ASUS is hard at work on their Socket 478 version of the P4T, but we don't know when it will be available. The same goes for Gigabyte and MSI, Intel's other launch partners for the 850 chipset.