Intel Pentium III Xeon 667 2.8V socket: Slot 2

What the Pentium III Xeon 667 2.8V is

The Intel Pentium III Xeon 667 2.8V 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 2.8 V regulator path.

Direct regulation with matching clocks and cache gives buyers a rail choice, which is why server lines stock one string or the other. Intel launched both 667 strings on October 25, 1999. The chip supports MMX, SSE and two-way SMP.

Matching clocks with direct feed suit 2.8 V Slot 2 lines. That is why the 2.8V string shipped in 2.8 V workgroup servers.

Socket and motherboard compatibility

The 667 2.8V fits Slot 2 servers wired for 2.8 V regulation. It needs a 330-lead SC330 board with a 133 MT/s bus and a BIOS that lists the 2.8 V 667 string. The Socket vs chipset: what decides whether a CPU works guide covers pairing rules.

2.8 V workgroup 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 5V-12V such as Intel Pentium III Xeon 667 5V-12V keeps clocks while changing regulator path. A Xeon 733 2.8V such as Intel Pentium III Xeon 733 2.8V adds clocks.

A move to Tanner Xeon drops to 100 MT/s paths. The Slot 2 page lists the range.