Intel Mobile Pentium III 400 socket: Micro-BGA2

What the Mobile Pentium III 400 is

The Intel Mobile Pentium III 400 is a 400 MHz single-core soldered mobile processor from October 1999. It runs one P6 Coppermine core at 400 MHz with no turbo, so 1 core gives 1 thread. Cache is 256 KB of full-speed L2 with 32 KB of L1 on a 180 nm process. Power is rated at 10.1 W max in a Micro-BGA2 soldered package with 495 balls on a 100 MHz front side bus with a 4x multiplier at 1.35 V.

The lowest mobile Coppermine clock opens the BGA line with a 10 W class envelope, which is why the 400 suits passively cooled sub-notebooks. Intel sold the Mobile 400 in October 1999 at $348. The chip supports MMX, SSE and QuickStart.

Entry mobile clocks with a tiny envelope suit soldered sub-notebooks with SDRAM. The 4x integer ratio is the lowest mobile multiplier. That is why the 400 shipped in mini laptops.

Socket and motherboard compatibility

The 400 is soldered to Micro-BGA2 boards and cannot be replaced. It fits mini boards with BGA2 solder lands, a 100 MHz bus and a BIOS that lists Mobile Pentium III 400. The Socket vs chipset: what decides whether a CPU works guide covers pairing rules.

Mini SDRAM boards are the natural match. Boards built for the 400 carry the soldered chip with a board spreader for the 10 W class.

Memory, PCIe and cooling

Memory is SDRAM through the board chipset at the 100 MHz bus rate, set by the board. The soldered CPU has no memory controller. Mini boards commonly pair PC100 SDRAM.

A 100 MHz front side bus ties the soldered chip to the chipset, while expansion hangs off the chipset. No PCIe lanes originate on the die. Thermal design is board-level with a spreader.

Upgrade paths

There is no CPU upgrade path from a soldered 400. The chip cannot move to a faster part. A board or system replacement is the only move.

For socketed planning, a Mobile Pentium III 450 such as Intel Mobile Pentium III 450 shows the socketed line on Socket 495. The Micro-BGA2 page lists the soldered range.