Intel Pentium III Xeon 800 2.8V socket: Slot 2

What the Pentium III Xeon 800 2.8V is

The Intel Pentium III Xeon 800 2.8V is an 800 MHz single-core server processor from January 2000. It runs one P6 Cascades core at 800 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 25.4 W in a Slot 2 SECC cartridge on a 133 MT/s front side bus with a 6x multiplier on the 2.8 V regulator path.

Direct regulation with the same clocks and cache as the 5V-12V string gives buyers a choice of rails, which is why server lines stock one or the other. Intel launched both 800 strings in January 2000. 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 800 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 800 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 25.4 W heatsinks.

Memory, PCIe and cooling

Memory is registered ECC 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 800 5V-12V such as Intel Pentium III Xeon 800 5V-12V keeps clocks while changing regulator path. A Xeon 866 2.8V such as Intel Pentium III Xeon 866 2.8V adds clocks.

A move to Foster Xeon needs Socket 603. The Slot 2 page lists the range.