Intel Mobile Pentium 4 HT 518 socket: Socket 478

What the Mobile Pentium 4 HT 518 is

The Intel Mobile Pentium 4 HT 518 is a 2.8 GHz single-core mobile 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 88 W in a Socket 478 package with part numbers RK80546HE0721M.

The 518 opens the Mobile Pentium 4 HT Prescott line for large notebooks, using a 533 MT/s front side bus with a 21x multiplier at 1.25 V to 1.40 V. Intel sold it at 202 dollars in June 2004. The chip supports MMX, SSE, SSE2 and SSE3 with Hyper-Threading. Desktop Prescott 2.80A parts at the same 2.8 GHz offer 89 W operation in towers, so the mobile 518 trades 1 W for notebook power handling without changing throughput.

Large notebook scope explains the high power for a mobile part. The 88 W envelope needs a thick desktop-replacement chassis with a large heat pipe assembly, not a thin ultraportable body. Buyers chose the 518 for desktop-like clocks on the road, accepting wall power operation and fan noise.

Socket and motherboard compatibility

The Mobile 518 fits Socket 478 desktop-replacement notebooks with DDR memory, a 533 MT/s bus and mobile Prescott HT BIOS support. It needs a notebook board with Socket 478 lands and mobile power delivery. The Socket vs chipset: what decides whether a CPU works guide covers pairing rules.

Large DDR notebooks are the natural match. The maker qualifies the exact mobile part for the heat pipe assembly, since desktop Prescott parts at similar clocks use different power tables. Thin notebooks with Socket 479 Pentium M parts need a different socket and lower power design.

Memory, PCIe and cooling

Memory is DDR through the board chipset, with SO-DIMM slots fixed by the notebook. Speed follows the 533 MT/s bus. The CPU has no memory controller.

A 533 MT/s bus ties the CPU to the mobile chipset, while graphics hangs off the chipset. No PCIe lanes originate on the die. Cooling is the notebook heat pipe assembly for an 88 W mobile chassis with strong fan curves. Dust control and fresh paste matter more than in towers, since notebook pipes clog quickly.

Upgrade paths

On Socket 478 the mobile steps are the Mobile Pentium 4 HT 532 at 3.06 GHz and the 538 at 3.2 GHz for larger chassis where listed. Desktop Prescott 2.80A parts offer the same clocks in towers with desktop cooling. Pentium M Dothan parts on Socket 479 offer far lower power for thin notebooks where battery life matters. The 518 removes with the socket mechanism, so qualified swaps need no solder work.