Intel Pentium 4 HT 520 socket: LGA 775

What the Pentium 4 HT 520 is

The Intel Pentium 4 HT 520 is a 2.8 GHz single-core desktop processor with Hyper-Threading from June 2004. It runs one NetBurst Prescott core at 2.8 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 84 W in an LGA 775 package with part numbers JM80547PG0721M. A cpu_list row repeats the 520 at 2.933 GHz, which conflicts with the table 2.8 GHz, and the table 2.8 GHz value is used here with three matching rows at 2.8 GHz.

The 520 uses an 800 MT/s front side bus with a 14x multiplier at 1.20 V to 1.425 V. Intel sold it at 178 dollars in June 2004 as the entry Hyper-Threading Prescott on LGA 775. The chip supports MMX, SSE, SSE2 and SSE3 with Hyper-Threading. A 520J shares clocks with Execute Disable support from October 2004, so feature flags separate the revisions. Socket 478 2.8E parts at the same clocks offer a pin grid alternative with the same cache.

Entry Hyper-Threading positioning made the 520 the office multitasking choice on LGA 775. The second thread helps during antivirus scans and media encoding on single-core towers, which is why the 520 cost more than the non-HT 511 at the same 2.8 GHz despite identical cache.

Socket and motherboard compatibility

The Pentium 4 HT 520 fits LGA 775 desktops with DDR or DDR2 memory, an 800 MT/s bus and Prescott HT BIOS support. It needs a land grid board with Hyper-Threading paths. The Socket vs chipset: what decides whether a CPU works guide covers pairing rules.

DDR office towers with 800 MT/s chipsets are the natural match. Intel 915 boards accept the chip with an 84 W cooler. Boards listing the 520 normally accept the 520J with a BIOS update for Execute Disable.

Memory, PCIe and cooling

Memory is DDR or DDR2 through the board chipset. The board sets speed and capacity.

An 800 MT/s bus ties the CPU to the chipset, while PCIe or AGP slots hang off the chipset for graphics. No PCIe lanes originate on the die. Cooling uses the LGA 775 plate with an 84 W heatsink. Normal airflow suits the envelope.

Upgrade paths

On LGA 775 the steps are the Pentium 4 HT 530 at 3 GHz and the 540 at 3.2 GHz with the same cache. The 520J at the same clocks adds Execute Disable support. Non-HT 511 parts offer the same frequency without threads. The 520 lifts with the load plate, so swaps need no solder work.