AMD Opteron 848 socket: Socket 940

What the Opteron 848 is

The AMD Opteron 848 is a 2.2 GHz single-core server processor from May 2004. It runs one K8 core at 2.2 GHz with no turbo, so 1 core gives 1 thread. Cache is 1 MB of L2 on a 130 nm process. Power is rated at 89 W in a Socket 940 package with part number OSA848CEP5AV in the CG stepping.

The 848 moves the 800 series into the 89 W class, using a 200 MHz clock with an 11x multiplier at 1.50 V and an 800 MHz HyperTransport link. AMD listed it at 1165 dollars in May 2004, against 3199 dollars for the C0 revision in November 2003. The chip supports MMX, SSE, SSE2, Enhanced 3DNow, NX bit and AMD64 with registered PC3200 DDR. The price drop from C0 to CG reflects stepping maturity, not a spec cut, since clocks and cache stayed flat while power delivery improved.

High clocks with multi-socket scale suited large shared-memory systems. Eight 848 parts give eight cores at 17.6 GHz of aggregate clocks with 8 MB of total L2, which suited database nodes that scaled with socket count. That scale is why 800 series top bins cost more than 200 series parts at the same frequency.

Socket and motherboard compatibility

The Opteron 848 fits Socket 940 multi-processor boards with registered DDR and SledgeHammer 800 series support at 89 W. It needs a four- or eight-socket board qualified for top-bin power. The Socket vs chipset: what decides whether a CPU works guide covers pairing rules.

Large coherent servers are the natural match. Boards listing 800 series parts at 89 W accept the 848 with matched heatsinks. Power delivery must handle top-bin current across all sockets, so maker qualification matters. Single-socket 148 and dual-socket 248 parts at the same 2.2 GHz do not scale to eight sockets.

Memory, PCIe and cooling

Memory is registered DDR with ECC per socket, reaching PC3200. Balanced DIMM populations across all sockets give full coherent bandwidth for large working sets. Server modules only.

HyperTransport at 800 MHz meshes sockets and the chipset, while expansion hangs off the chipset. No PCIe lanes originate on the die. Cooling uses 89 W qualified heatsinks per socket with strong chassis airflow. Top-bin operation needs clean filters and healthy fans, since heat rises quickly across eight sockets. DDR2 needs later sockets.

Upgrade paths

On Socket 940 the step is the Opteron 850 at 2.4 GHz at the same 89 W for multi-socket boards. Athens 848 successors on 90 nm add SSE3 where listed. Beyond Socket 940 a move to Socket G34 needs new boards. The 848 lifts with the lever, so swaps need no solder work.