Intel Pentium 4 HT 3.0E socket: Socket 478

What the Pentium 4 HT 3.0E is

The Intel Pentium 4 HT 3.0E is a 3 GHz single-core desktop processor with Hyper-Threading from February 2004. It runs one NetBurst Prescott core at 3 GHz with no turbo, so 1 core gives 2 threads. Cache is 1 MB of L2 on a 90 nm process. Power is rated at 89 W in a Socket 478 package with part numbers RK80546PG0801M. The cpu_list 115 W value differs from the table 89 W, and the table value is used here.

The 3.0E uses an 800 MT/s front side bus with a 15x multiplier at 1.20 V to 1.425 V. Intel sold it at 218 dollars in February 2004. The chip supports MMX, SSE, SSE2 and SSE3 with Hyper-Threading. Later G1 steppings trim power against early C0 parts at the same clocks. An LGA 775 530 at the same 3 GHz shares frequency with a land grid package, so socket decides the board.

Flat power from 2.8E to 3.0E simplified upgrades. A Socket 478 board qualified for the 2.8E at 89 W normally accepts the 3.0E with the same heatsink, since only the multiplier rises. That drop-in path made the 3.0E a common speed lift for office towers.

Socket and motherboard compatibility

The Pentium 4 HT 3.0E fits Socket 478 desktops with DDR memory, an 800 MT/s bus and Prescott HT support. It needs a 478-pin board with 90 nm microcode. The Socket vs chipset: what decides whether a CPU works guide covers pairing rules.

DDR towers with 800 MT/s chipsets are the natural match. Intel 865 boards accept the chip with an 89 W cooler. LGA 775 530 parts need land grid boards instead.

Memory, PCIe and cooling

Memory is DDR through the board chipset. The board sets speed and capacity.

An 800 MT/s bus ties the CPU to the chipset, while AGP handles graphics. No PCIe lanes originate on the die. Cooling uses the Socket 478 bracket with an 89 W heatsink. Normal airflow suits the envelope.

Upgrade paths

On Socket 478 the steps are the Pentium 4 HT 3.2E at 3.2 GHz and the 3.4E at 3.4 GHz with the same cache. Northwood HT 3.0 parts offer a 512 KB alternative. Beyond Socket 478 a move to LGA 775 needs a new board. The 3.0E lifts with the lever, so swaps need no solder work.