Intel Pentium 4 HT 3.4E socket: Socket 478

What the Pentium 4 HT 3.4E is

The Intel Pentium 4 HT 3.4E is a 3.4 GHz single-core desktop processor with Hyper-Threading from April 2004. It runs one NetBurst Prescott core at 3.4 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 115 W in a Socket 478 package with part numbers RK80546PG0961M. The table lists the Socket 478 3.40 GHz E part from February 2004 with 1 MB of cache, while LGA 775 3.4F parts carry the same 115 W rating from August 2004, and the 115 W value is used here for the Socket 478 E bin with FMB1.5 power handling.

The 3.4E tops the Socket 478 Prescott HT line with an 800 MT/s front side bus and a 17x multiplier at 1.20 V to 1.425 V. Intel sold LGA 775 550 parts at the same 3.4 GHz and 115 W from June 2004 at 417 dollars, which places the Socket 478 E bin as the pin grid twin for late DDR towers. The chip supports MMX, SSE, SSE2 and SSE3 with Hyper-Threading. Northwood HT 3.40 parts at the same clocks offer 512 KB of cache at 89 W as a cooler alternative, while Gallatin EE 3.40 parts add 2 MB of L3 cache at 102.9 W.

Top clocks on Socket 478 need strong cooling. The move from 103 W on the 3.2E to 115 W on the 3.4E raises heatsink and airflow needs, even though the socket and bus stay flat. That is why only boards with FMB1.5 power delivery and a BIOS that lists 3.4E parts run the chip at full stability.

Socket and motherboard compatibility

The Pentium 4 HT 3.4E fits Socket 478 desktops with DDR memory, an 800 MT/s bus, FMB1.5 power delivery and Prescott HT BIOS support. It needs a 478-pin board qualified for 115 W operation. The Socket vs chipset: what decides whether a CPU works guide covers pairing rules.

Late performance DDR towers with Intel 875 chipsets are the natural match. Boards listing 3.4E parts accept the chip with a 115 W cooler on the Socket 478 bracket. Boards limited to 89 W or 103 W Prescott parts need a power check before fitting the top bin. LGA 775 550 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 a 115 W heatsink and strong case airflow. Clean vents and fresh paste matter at the top of the Socket 478 power range.

Upgrade paths

On Socket 478 the 3.4E tops Prescott HT, so same socket upgrades stop here apart from Gallatin EE 3.40 parts with L3 cache where listed. Northwood HT 3.40 offers lower power without the 1 MB cache. Beyond Socket 478 a move to LGA 775 needs a new board, with 550 parts as successors. The 3.4E lifts with the lever, so swaps need no solder work.