Intel Core Duo ULV L2400 socket: Socket 479

What the Core Duo ULV L2400 is

The Core Duo ULV L2400 is a dual-core Yonah processor built for slim notebooks that still wanted two threads. Two 65 nm Yonah cores share 2 MB of L2 cache and run together at 1.07 GHz, giving two threads with no turbo stage. A 533 MT/s front side bus links the pair to the chipset. The 9 W rating places it in the ultra low voltage dual-core class, above the 5.5 W Solo parts and well below the 15 W low voltage line.

Naming needs a short note. The Wikipedia mobile list carries this 1.07 GHz 9 W dual-core Yonah as the U2400 with a June 2006 date, while the TechPowerUp database catalogs the same 1066 MHz 9 W part as the L2400 with a September 2006 date. Clocks, cache, bus and power match across both entries, so this page follows the mobile list values and its June 2006 date. Either label points at the same soldered 479-ball chip.

The locked 8x multiplier yields 1.07 GHz from the 533 MT/s bus. Shared cache logic lets either core use the full 2 MB when the other idles, which helps single-threaded bursts inside a dual-core chip. Enhanced Intel SpeedStep lowers clock and voltage at rest, stretching battery life between mains sockets. Media support covers MMX, SSE, SSE2 and SSE3, while 64-bit addressing stays absent across Yonah, so a 32-bit operating system is required.

Against its ULV peers, the L2400 is the entry dual-core option. The L2500 ULV repeats the 9 W formula at 1.2 GHz for heavier multitasking, and the Solo ULV chips trade the second core for a 5.5 W ceiling. Buyers who ran office suites with background tasks felt the second core more than the modest clock. Machines of this class paired the chip with small screens and light chassis, where every watt showed up in battery time.

Socket and motherboard compatibility

The ULV L2400 is soldered to its board and cannot be replaced, so the board carries the whole compatibility story. The 479-ball Micro-FCBGA package bonds to a Napa platform board from the Intel 945 chipset family at the factory. Firmware on that board names the exact fitted processor, and a donor board must name the same number or service code. The Socket vs chipset: what decides whether a CPU works guide explains how to check those maker records on mobile boards.

There is no path between this soldered Socket 479 part and the pinned Yonah chips of Socket M. Socket M takes removable Core Duo and Core Solo T series processors with a hinge socket and BIOS tables written for pins. Balls, firmware and mounting all differ here. A dead ULV board needs a board built for the same soldered dual-core number, not a socketed chassis with a close name.

Because ULV and LV numbers overlap, labels deserve care. A 1066 MHz 9 W chip and a 1666 MHz 15 W chip can both carry L2400 in different catalogs, so clock and power must be confirmed together. Match the service code and the rated wattage on the board sticker before ordering. The wrong 2400 would bring the wrong fan table and power limits with it.

Memory, PCIe and cooling

Memory for the ULV L2400 arrives through the chipset. Boards of the Napa generation fit DDR2 modules under the Intel 945 chipset, with the maker fixing slot count and module size. The processor reaches that memory over its 533 MT/s front side bus, so bus speed caps how quickly cache misses resolve. Maker approved DDR2 in matched sizes keeps the shared-cache dual core fed without errors.

PCI Express starts at the chipset, not the CPU. The L2400 exposes no lanes; its front side bus runs to the 945 chip, and slots, Mini PCI-E cards, CardBus bridges and storage attach beyond it. Graphics live in the chipset or in a discrete mobile GPU on the board. On a surviving subnotebook, memory size and drive speed shape daily pace more than the 1.07 GHz CPU mark.

Cooling matches the 9 W budget. A flat spreader or short heat pipe moves heat from the soldered package to a compact blower governed by firmware tuned for this chip. No boxed cooler and no mounting standard apply to the owner. Dust-choked outlets and dried paste cause most age-related warmth, and both yield to cleaning and fresh interface material.

Upgrade paths

No CPU upgrade exists for the ULV L2400. The soldered balls fix it to its board, and no service procedure lifts a 479-ball chip in the field. A faster Yonah cannot take its place, whether from the ULV or LV lines. The Intel Celeron 220 page records the same boundary for its soldered Socket 479 package, since the rule follows the package rather than the model.

Faster Yonah computing needs a board built for a quicker soldered part, or a whole newer notebook when the platform tires. Shoppers who want removable processors should consider socketed Yonah systems under Socket M, where pinned T series chips change within the maker list. The Socket vs chipset: what decides whether a CPU works guide lays out the verification steps for either direction.