Intel Pentium III Xeon 550 1MB socket: Slot 2

What the Pentium III Xeon 550 1MB is

The Intel Pentium III Xeon 550 1MB 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 1 MB 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.

Double cache over the plain 550 at matching clocks and power gives the 1MB string room for larger databases, which is why it headed workgroup servers in late 1999. Intel launched the 550 1MB on August 23, 1999 at $1980. The chip supports MMX, SSE and four-way SMP.

Balanced clocks with a large cache suit Slot 2 workgroup boards. That is why the 550 1MB shipped in dual and quad workgroup boxes.

Socket and motherboard compatibility

The 550 1MB fits Slot 2 workgroup servers with Tanner support. It needs a 330-lead SC330 board with a 100 MT/s bus and a BIOS that lists the 1MB Xeon 550. The Socket vs chipset: what decides whether a CPU works guide covers pairing rules.

Workgroup rack servers are the natural match. Boards listing the 1MB string accept 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. Workgroup 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 2MB such as Intel Pentium III Xeon 550 2MB doubles cache to 2 MB at equal power. A plain Xeon 550 such as Intel Pentium III Xeon 550 halves cache to 512 KB.

A move to Cascades Xeon adds 133 MT/s paths. The Slot 2 page lists the range. Note: the queue row lists 35 W; this page uses the verified 34 W shared by the 550 set.