Intel Pentium III Xeon 550 socket: Slot 2

What the Pentium III Xeon 550 is

The Intel Pentium III Xeon 550 is a 550 MHz single-core server processor from August 1999. It runs one P6 Tanner core at 550 MHz with no Hyper-Threading, so 1 core gives 1 thread. Cache is 512 KB of L2 at full CPU speed with 32 KB of L1 on a 250 nm process. Power is rated at 34 W in a Slot 2 SECC cartridge on a 100 MT/s front side bus with a 5.5x multiplier at 2.0 V.

The base 512 KB cache at a mid 550 MHz clock gives the plain 550 the lowest price in the 550 set, which is why it suited entry quad servers. Intel launched the plain 550 on August 23, 1999 at $931. The chip supports MMX, SSE and four-way SMP.

Balanced clocks with quad paths suit Slot 2 starter racks. The 5.5x half-ratio needs an exact BIOS string. That is why the plain 550 shipped in entry quad boxes.

Socket and motherboard compatibility

The 550 fits Slot 2 entry servers with Tanner support. It needs a 330-lead SC330 board with a 100 MT/s bus and a BIOS that lists the Xeon 550. The Socket vs chipset: what decides whether a CPU works guide covers pairing rules.

Entry quad servers are the natural match. Boards listing the plain 550 accept up to four cartridges with 34 W heatsinks each.

Memory, PCIe and cooling

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

A 100 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 550 1MB such as Intel Pentium III Xeon 550 1MB doubles cache to 1 MB at equal power when databases grow. A 550 2MB such as Intel Pentium III Xeon 550 2MB quadruples cache.

A move to Cascades Xeon adds 133 MT/s paths. The Slot 2 page lists the range. Note: the queue row lists April 1999; this page uses the verified August 23, 1999 shared by the 550 set.