Intel Mobile Pentium III 850 socket: Socket 495

What the Mobile Pentium III 850 is

The Intel Mobile Pentium III 850 is an 850 MHz single-core mobile processor from September 2000. It runs one P6 Coppermine core at 850 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 with 28 million transistors. Power is rated at 27.5 W max in a Socket 495 micro-PGA2 package on a 100 MHz front side bus with an 8.5x multiplier at 1.6 V high and 1.35 V battery mode.

SpeedStep drops the chip to 700 MHz at 1.35 V in battery mode with about 16 W, which is why the 850 suited thin laptops that need desktop bursts on AC. Intel sold the Mobile 850 in September 2000 with SpeedStep tables. The chip supports MMX, SSE, QuickStart and Deep Sleep. A soldered BGA2 counterpart with the same silicon exists for thinner boards; this page covers the socketed package per the socketed-only rule.

Upper mobile clocks with a full cache suit Socket 495 thin laptops with SDRAM. The micro-PGA2 package allows replacement with the socket lever. That is why the 850 shipped in thin-and-light laptops.

Socket and motherboard compatibility

The 850 fits Socket 495 thin laptops with Coppermine support. It needs a 495-pin micro-PGA2 board with a 100 MHz bus and a BIOS that lists Mobile Pentium III 850. The Socket vs chipset: what decides whether a CPU works guide covers pairing rules.

Thin SDRAM laptops are the natural match. Boards listing the Mobile 850 accept the chip with a 27.5 W heat pipe assembly. Soldered BGA2 boards cannot accept the pinned package.

Memory, PCIe and cooling

Memory is SDRAM through the board chipset, matched to the board slots. The CPU has no memory controller. Thin 440MX boards commonly run PC100 pairs.

A 100 MHz front side bus ties the CPU to the chipset, while AGP and PCI hang off the chipset. No PCIe lanes originate on the die. Cooling uses the laptop heat pipe for the exact chassis, rated for 27.5 W with SpeedStep tables.

Upgrade paths

On the same socket, a move to a Mobile Pentium III 1000 such as Intel Mobile Pentium III 1000 keeps the laptop for 150 MHz more at 25 W when the support list names it. A Mobile Pentium III 800 such as Intel Mobile Pentium III 800 drops 50 MHz at 25.9 W.

A move to Pentium III-M Tualatin needs 512 KB cache board support. The Socket 495 page lists the mobile range. Note: the queue row lists 18 W typical; this page uses the verified 27.5 W max.