Intel Pentium 4 HT Extreme Edition 3.20 socket: Socket 478

What the Pentium 4 EE 3.20 is

The Intel Pentium 4 HT Extreme Edition 3.20 is a 3.2 GHz single-core enthusiast processor with Hyper-Threading from November 2003. It runs one NetBurst Gallatin core at 3.2 GHz with no turbo, so 1 core gives 2 threads. Cache is 512 KB of L2 plus 2 MB of L3 on a 130 nm process. Power is rated at 92.1 W in a Socket 478 package with part number SL7AA.

The EE 3.20 opens the Gallatin Extreme Edition line with an 800 MT/s front side bus and a 16x multiplier at 1.55 V. Intel sold it at 925 dollars in November 2003 as the first enthusiast chip with server-derived L3 cache. The chip supports MMX, SSE and SSE2 with Hyper-Threading. Standard Northwood HT 3.20 parts at the same 3.2 GHz offer 512 KB without L3 at 82 W, so cache and power separate the bins at identical frequency.

Large L3 cache for games defines the premium over standard parts. The 2 MB L3 keeps more game data on die than 512 KB standard parts, which helps at the same 3.2 GHz clocks. That is why the EE 3.20 cost more than the standard HT 3.20 despite sharing frequency and bus.

Socket and motherboard compatibility

The EE 3.20 Socket 478 fits Socket 478 enthusiast desktops with DDR memory, an 800 MT/s bus and Gallatin EE BIOS support. It needs a 478-pin board with Gallatin microcode and 92.1 W power delivery. The Socket vs chipset: what decides whether a CPU works guide covers pairing rules.

High-end DDR towers with AGP 8x graphics are the natural match. Boards listing Gallatin EE parts accept the chip with a cooler rated above 90 W. Standard Northwood boards may seat the chip yet miss L3 cache paths without EE firmware.

Memory, PCIe and cooling

Memory is DDR through the board chipset, with dual channel operation on 875 boards for full bandwidth. The CPU has no memory controller.

An 800 MT/s bus ties the CPU to the chipset, while AGP 8x carries graphics. No PCIe lanes originate on the die. Cooling uses the Socket 478 bracket with a 92.1 W heatsink and strong airflow.

Upgrade paths

On Socket 478 the steps are the EE 3.40 Gallatin at 3.4 GHz with the same cache. Standard HT 3.20 offers the same clocks without L3 at lower power. Beyond Socket 478 a move to LGA 775 needs a new board with EE 3.40 and 3.46 parts. The EE chip lifts with the lever, so swaps need no solder work.