Intel Pentium III Xeon 550 2MB socket: Slot 2

What the Pentium III Xeon 550 2MB is

The Intel Pentium III Xeon 550 2MB 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 2 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.

The 2 MB flagship cache at a steady 34 W gives the 550 2MB the largest working set of the Tanner line at modest power, which is why it headed database servers in late 1999. Intel launched the 550 2MB on August 23, 1999 at $3692. The chip supports MMX, SSE and four-way SMP.

Mid Tanner clocks with flagship cache suit Slot 2 database boards with registered memory. The 5.5x half-ratio needs an exact BIOS string. That is why the 550 2MB shipped in quad database boxes.

Socket and motherboard compatibility

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

Database rack servers are the natural match. Boards listing the 2MB 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. Database boards commonly interleave 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 halves cache to 1 MB at equal power when budgets tighten. A plain Xeon 550 such as Intel Pentium III Xeon 550 drops 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 41 W; this page uses the verified 34 W shared by all three 550 cache options.