AMD Opteron 854 socket: Socket 940

What the Opteron 854 is

The AMD Opteron 854 is a 2.8 GHz single-core server processor from August 2005. It runs one K8 core at 2.8 GHz with no turbo, so 1 core gives 1 thread. Cache is 1 MB of L2 on a 90 nm process. Power is rated at 92 W on Socket 940.

The 854 topped the Athens 800 series with registered DDR memory on a 1000 MT/s HyperTransport link at about 1514 dollars launch price. It exists because multi-socket buyers wanted the fastest Athens single core with the full 1 MB cache.

Socket and motherboard compatibility

The 854 fits Socket 940 multi-socket server boards with a BIOS that lists late Athens parts. It suits performance racks qualified for 92 W parts with registered DDR slots. Check the server maker CPU list for the exact board and stepping. The Socket vs chipset: what decides whether a CPU works guide covers pairing rules.

Memory, PCIe and cooling

Memory is registered DDR in two channels through the on-chip controller.

HyperTransport at 1000 MT/s links the CPU to the chipset and other sockets. PCIe slots hang off the chipset.

Cooling uses vendor qualified server heatsinks for the 92 W envelope with directed airflow.

Upgrade paths

On Socket 940 the upgrade stays within Athens, as the 854 tops the 800 series. The AMD Opteron 852 at 2.6 GHz drops clocks with the same 1 MB cache. Beyond Socket 940 a move to Socket F needs new boards and DDR2 memory.