Intel Pentium M 730 socket: Socket 479

What the Pentium M 730 is

The Pentium M 730 opened the Sonoma refresh of the Pentium M line in January 2005. It runs one Dothan core at 1.6 GHz with no turbo step, so the clock stays fixed under load and at idle apart from SpeedStep drops. The core carries 2 MB of L2 cache, double the amount on the earlier Banias parts, which helps office programs and web browsing keep working sets on chip. Intel built the die on the 90 nm process with about 144 million transistors on an 87 mm2 die, a size TechPowerUp lists for the whole 730 to 780 set.

A 12x multiplier sets the pace against a 133 MHz base clock, giving the rated 1.6 GHz on a 533 MT/s front side bus. The multiplier is locked, so the board decides the bus and the chip follows it. There is no 64 bit support in this design, and the instruction set stops at SSE2 with the NX bit for execute protection. For a notebook sold in early 2005 that combination was normal, and surviving machines still run a 32 bit operating system with period drivers.

Intel positioned the 730 as the entry point of the 533 MT/s Dothan stack. It shares the 27 W thermal rating with the faster 740 to 780 models, which means a notebook cooler drawn for the line handles any of them. The same SKU also shipped in a soldered Micro-FCBGA twin for boards that never had a socket, while this page covers the socketed Micro-FCPGA package. A buyer who finds a 730 in a used notebook gets the slowest clock of the refresh with the full 2 MB cache and the lower heat of a single core design.

Socket and motherboard compatibility

This chip fits a lever actuated ZIF socket with 479 holes in the mPGA479M layout. The pins drop in with no force and the lever locks them in place, which is the whole reason socketed mobile parts can move between boards. Only 478 pins carry signals, since one position stays reserved, and that detail is why Socket 478 desktop boards cannot accept this processor despite the close pin count. The Socket 479 page sets out the hole count and the mPGA478C naming.

Sonoma notebooks on 915 series mobile chipsets are the natural home for the 730. Those boards run the 533 MT/s bus the chip needs and carry DDR2 slots beside it. Older 855 series boards were drawn for 400 MT/s Banias traffic and do not make a safe home for a 533 MT/s Dothan part, even where the chip seats. The Socket vs chipset: what decides whether a CPU works guide explains why the socket name alone never settles a mobile fit.

Board firmware must list the exact sSpec stepping before a swap counts as supported. Intel sold the 730 under sSpec codes such as SL86G, and notebook makers copied those codes into BIOS support tables. A board that lacks the code may fail to boot or may misreport the clock. The soldered Micro-FCBGA twin of the 730 solders straight to the board with no socket at all, so it never enters the used socketed market. Socket M arrived in 2006 as the successor with a shifted pin for Core processors, and Socket M parts are incompatible with these boards.

Memory, PCIe and cooling

Memory on a 730 notebook is DDR2 fitted through the board chipset. The processor itself holds no memory controller, so slot count, module size limits, and approved speeds come from the notebook maker. A matched pair of maker approved modules keeps the 533 MT/s front side bus fed during cache misses. Boards of this era commonly accepted DDR2 400 or DDR2 533 depending on the chipset strap, and the manual for the exact notebook model gives the ceiling.

There are no PCI Express lanes inside the processor. The front side bus at 533 MT/s carries CPU traffic to the chipset, and graphics plus expansion hang off the chipset side. Some Sonoma boards pair the 730 with chipset graphics while others add a separate mobile GPU on the board. Either way the graphics driver comes from the notebook maker or the chipset vendor rather than from the CPU.

Cooling follows the vendor heat pipe sized for 27 W. A copper plate over the bare die feeds one or two heat pipes that run to a side fan outlet, and the firmware fan table is tuned for that load. The die ships without a heat spreader, so a repaste needs a thin even layer and gentle mount pressure. Fresh thermal material and a clean fan restore the original acoustic profile when an old machine runs loud at idle.

Upgrade paths

A 730 board that already runs can step up within the same socket where the BIOS allows it. The 740 at 1.73 GHz, the 750 at 1.86 GHz, the 760 at 2.0 GHz, the 770 at 2.13 GHz, and the 780 at 2.26 GHz all share the 2 MB cache, the 533 MT/s bus, and the 27 W rating, so the thermal side needs no change. Each step keeps the same single core and single thread layout and raises the locked multiplier by one or more steps. Check the maker CPU support list for the exact sSpec before buying a donor chip.

A move past the 780 leaves Socket 479 behind. Core Duo and later mobile processors need the Socket M successor with its changed pin and new chipset, which means a different notebook or a different board. The Socket vs chipset: what decides whether a CPU works guide shows how to confirm chipset and firmware support before spending money on either path. For a machine that already feels slow in daily use, extra memory and a solid state drive on the original board often help more than a small clock step.