Intel Core Solo ULV U1400 socket: Socket 479

What the Core Solo ULV U1400 is

The Core Solo ULV U1400 is a single-core Yonah processor that reached thin notebooks in April 2006. One 65 nm Yonah core runs at 1.2 GHz, giving a single thread of execution with no turbo mode on top. The cache and bus match the rest of the Solo ULV line: 2 MB of L2 cache beside the core and a 533 MT/s front side bus toward the chipset. Intel placed the chip a step above the 1.07 GHz U1300 for buyers who wanted a little more pace without leaving the 5.5 W envelope.

The locked 9x multiplier produces the 1.2 GHz clock from the 533 MT/s bus. Operation stays simple, with one fixed ceiling and Enhanced Intel SpeedStep trimming clock and voltage when the machine idles. Media extensions cover MMX, SSE, SSE2 and SSE3, which helps audio and video playback on period software. As with all Yonah silicon, there is no 64-bit support, so only a 32-bit operating system fits these boards.

Power defines the part more than speed does. The 5.5 W rating is the lowest Yonah class, shared with the U1300 below and the later U1500 above, and it lets makers build slim machines with modest cooling. The Micro-FCBGA 479 package solders to the board with 479 balls, which removes any socket, lever or retention frame from the picture. Heat flows into a maker fitted plate or heat pipe. Firmware owns the fan curve, and servicing means cleaning plus fresh thermal material.

Against its neighbors, the U1400 is the middle Solo ULV choice. It adds roughly 12 percent clock over the U1300 while the paper power stays flat at 5.5 W. The U1500 later pushed the same formula to 1.33 GHz in January 2007. Anyone needing parallel work rather than a slightly quicker single thread looked to the dual-core ULV parts at 9 W, which trade battery time for a second core.

Socket and motherboard compatibility

The U1400 is soldered to its board and cannot be replaced, so board identity decides everything. Its 479-ball package bonds to a Napa platform board from the Intel 945 chipset family, and the board firmware carries the only compatibility list that matters. A donor board must name the U1400 or its service code in the maker records. The Socket vs chipset: what decides whether a CPU works guide describes how to read those maker lists for mobile boards.

That soldered Socket 479 package has no exchange with the pinned Yonah world of Socket M. Socket M boards take removable Core Solo and Core Duo T series processors with their own chipset and BIOS tables. Balls versus pins, different firmware, different mounting: the two lines never meet. A dead U1400 board calls for a board built around the same soldered number, not for a socketed chassis with a similar name.

Clock differences inside the ULV line make exact matching important. The U1300, U1400 and U1500 share ball pattern and power class yet run at 1.07, 1.2 and 1.33 GHz with different multipliers. Ordering by marketing name alone risks a board tuned for the wrong clock. Confirm the service code on the board sticker or in the manual before committing.

Memory, PCIe and cooling

System memory connects through the chipset, since the processor carries no memory controller. Boards for the U1400 use DDR2 modules on the Intel 945 based Napa platform, and the maker decides slot count plus the largest module per slot. Traffic between CPU and memory crosses the 533 MT/s front side bus. Matched pairs of approved DDR2 sticks give the most stable result on boards with two slots, while single-slot subnotebooks take what fits.

PCI Express comes from the chipset as well. The U1400 contributes no lanes of its own; its external link is the front side bus to the 945 chipset, and slots, CardBus bridges, wireless and storage all attach downstream of that chip. Onboard graphics, where present, sit in the chipset silicon rather than in the processor. Judging a surviving machine by its disk, memory size and chipset graphics says more than judging it by the 1.2 GHz CPU clock.

Thermal design stays small because the budget is only 5.5 W. Makers typically fit a thin spreader plate across the soldered package with a short path to a small blower. No boxed cooler exists and no socket pattern applies. Age-related heat trouble usually traces to dust in the outlet or dried interface material, both fixed with basic service rather than new parts.

Upgrade paths

No processor swap exists for the U1400. Soldered balls hold it to the board, and field rework of a 479-ball package is not a service option. A quicker Yonah cannot be dropped in, even from within the same ULV family. The Intel Celeron 220 page states the identical limit for its own soldered Socket 479 design, showing that the package rule holds across families.

The way forward is a board built for a quicker soldered Yonah, or a complete newer notebook when the platform as a whole feels slow. Shoppers who want a chip they can change should look at socketed Yonah machines under Socket M, where the maker support list permits swaps. The Socket vs chipset: what decides whether a CPU works guide explains the checks for both routes.