Intel Pentium 4 1.4 socket: Socket 478

What the Pentium 4 1.4 is

The Intel Pentium 4 1.4 is a 1400 MHz single-core desktop processor from August 2001 in Socket 478 form. It runs one NetBurst Willamette core at 1400 MHz with no Hyper-Threading, so 1 core gives 1 thread. Cache is 256 KB of L2 on a 180 nm process with 42 million transistors. Power is rated near 55.3 W in a Socket 478 FC-PGA2 package with part numbers SL5N7 and SL59U on a 400 MT/s front side bus with a 14x multiplier at up to 1.75 V.

The Socket 478 Willamette refresh moves the 1.4 from the short-lived 423 package to the long-lived 478 package at matching clocks, which is why 478 boards accept this 1.4 while 423 boards need the older string. Intel sold Socket 478 1.4 parts from August 2001 with the 1.5 and 1.6 parts. The chip supports MMX, SSE and SSE2.

Early 478 clocks with RDRAM and SDRAM chipset options suit first Socket 478 towers with AGP graphics. The 55 W envelope needs a standard 478 cooler. That is why the 1.4 shipped in early Socket 478 systems with SDRAM cost options.

Socket and motherboard compatibility

The 1.4 fits Socket 478 early desktops with Willamette support. It needs a 478-pin board with a 400 MT/s bus and a BIOS that lists Pentium 4 1.4 Willamette. The Socket vs chipset: what decides whether a CPU works guide covers pairing rules.

Early SDRAM and RDRAM towers are the natural match. Boards listing the Socket 478 1.4 accept the chip with a 55 W cooler. Socket 423 boards cannot accept the 478-pin package.

Memory, PCIe and cooling

Memory is SDRAM, DDR and RDRAM through the board chipset by board generation, matched to the board slots. The CPU has no memory controller. Early 478 boards commonly run PC133 SDRAM or PC800 RDRAM pairs for 400 MT/s parts.

A 400 MT/s front side bus ties the CPU to the chipset, while AGP and PCI hang off the chipset. No PCIe lanes originate on the die. Cooling uses the Socket 478 bracket with a cooler rated for 55 W.

Upgrade paths

On the same socket, a move to a Pentium 4 1.5 such as Intel Pentium 4 1.5 keeps the board and memory when the support list names it. The 1.5 adds 100 MHz at 58 W, so the cooler stays close. A Pentium 4 HT 3.6E such as Intel Pentium 4 HT 3.6E is a far later Prescott part needing its own power tables.

A move to Northwood needs a BIOS with 512 KB cache strings. The Socket 478 page lists the Willamette to Gallatin range for planning.