AMD Opteron 840 EE socket: Socket 940

What the Opteron 840 EE is

The AMD Opteron 840 EE is a 1.4 GHz energy-efficient single-core server processor from May 2004. It runs one K8 core at 1.4 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 30 W in a Socket 940 package with part number OSB840CSP5AV in the CG stepping.

EE bins the multi-socket 840 rating from 82 W down to 30 W at 1.15 V with identical clocks and cache. AMD listed the EE bin at 1514 dollars in May 2004, against 698 dollars for the standard 840. The premium bought lower heat per socket for dense four- and eight-socket racks where power feeds limit node count. The chip supports MMX, SSE, SSE2, Enhanced 3DNow, NX bit and AMD64 with registered PC3200 DDR and an 800 MHz HyperTransport link.

Dense multi-socket use is the point. Eight 840 EE parts at 30 W each give eight cores at 240 W of CPU power, against 656 W for standard parts. That gap lets large shared-memory systems fit existing power and cooling, which mattered for database clusters with many sockets.

Socket and motherboard compatibility

The 840 EE fits Socket 940 multi-processor dense servers with registered DDR and EE SledgeHammer BIOS support. It needs a multi-socket board qualified for 30 W EE operation. The Socket vs chipset: what decides whether a CPU works guide covers pairing rules.

Dense four- and eight-socket chassis are the natural match. Boards listing EE 800 series parts set voltage to 1.15 V with low power fan curves. Standard power boards may seat the chip yet miss EE tables. Single-socket boards need 100 series EE parts instead.

Memory, PCIe and cooling

Memory is registered DDR with ECC per socket, reaching PC3200. Each socket needs DIMMs for balanced coherent bandwidth. Server modules only.

HyperTransport at 800 MHz links all sockets coherently and to the chipset, while expansion hangs off the chipset. No PCIe lanes originate on the die. Cooling uses low power qualified heatsinks per socket with shared rack airflow. Dense packing still needs clean filters, since many low power sockets share limited air. DDR2 needs later platforms.

Upgrade paths

On Socket 940 EE multi-socket growth stays inside EE bins, with standard power 842 and 844 parts as higher clock alternatives where cooling allows. Athens successors on 90 nm offer SSE3 paths where listed. Beyond Socket 940 a move to newer multi-socket sockets needs new boards. The 840 EE lifts with the lever, so swaps need no solder work.