Intel Pentium III Xeon 667 5V-12V socket: Slot 2

What the Pentium III Xeon 667 5V-12V is

The Intel Pentium III Xeon 667 5V-12V is a 667 MHz single-core server processor from October 1999. It runs one P6 Cascades core at 667 MHz with no Hyper-Threading, 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 21.3 W in a Slot 2 SECC cartridge on a 133 MT/s front side bus with a 5x multiplier on the 5V-12V regulator path.

A 5x integer ratio on the fast bus gives the 667 clean timing, which is why it became a common workgroup pick. Intel launched the Xeon 667 on October 25, 1999 at $655. The chip supports MMX, SSE and two-way SMP.

Balanced clocks with a 21 W class envelope suit Slot 2 workgroup boards. That is why the 667 5V-12V shipped in dual workgroup boxes.

Socket and motherboard compatibility

The 667 5V-12V fits Slot 2 workgroup servers with 5V-12V regulation. It needs a 330-lead SC330 board with a 133 MT/s bus and a BIOS that lists the 5V-12V 667 string. The Socket vs chipset: what decides whether a CPU works guide covers pairing rules.

Workgroup rack servers are the natural match. Boards listing the string accept cartridges with 21.3 W heatsinks.

Memory, PCIe and cooling

Memory is registered SDRAM through the server chipset, matched to the board sockets. The cartridge has no memory controller. Workgroup boards commonly run ECC pairs.

A 133 MT/s front side bus ties each cartridge to the chipset, while PCI hangs off the chipset. No PCIe lanes originate on the cartridge. Cooling uses SECC heatsinks on the retention cage.

Upgrade paths

On the same slot, a move to a Pentium III Xeon 667 2.8V such as Intel Pentium III Xeon 667 2.8V keeps clocks and cache while changing regulator path. A Xeon 733 5V-12V such as Intel Pentium III Xeon 733 5V-12V adds clocks.

A move to Tanner Xeon drops to 100 MT/s paths. The Slot 2 page lists the range. Note: the queue row lists 21 W; this page uses the verified 21.3 W.