AMD Opteron 242 socket: Socket 940

What the Opteron 242 is

The AMD Opteron 242 is a 1.6 GHz single-core server processor from May 2004. It runs one K8 core at 1.6 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 82 W in a Socket 940 package with part number OSA242CEP5AU in the CG stepping.

The 242 lifts the 200 series from the 1.4 GHz 240 with the same cache and power, using a 200 MHz clock with an 8x multiplier at 1.50 V and an 800 MHz HyperTransport link. AMD listed it at 209 dollars in May 2004, against 690 dollars for the B3 revision in April 2003. The chip supports MMX, SSE, SSE2, Enhanced 3DNow, NX bit and AMD64 with registered PC3200 DDR. A Troy Opteron 242 on 90 nm shares the model number with different power and SSE3 support, so codename decides board expectations. This page covers the SledgeHammer CG part, since it matches the May 2004 82 W listing.

Two-socket use defines the 242. The leading 2 enables coherent operation with a second 242 on a dual-processor board, doubling cores per chassis. That pairing suited workgroup servers where two 1.6 GHz cores with 1 MB each beat a single faster core.

Socket and motherboard compatibility

The Opteron 242 SledgeHammer fits Socket 940 dual-processor boards with registered DDR and SledgeHammer 200 series BIOS support. It needs a two-socket board, not a single-socket 100 series board. The Socket vs chipset: what decides whether a CPU works guide covers pairing rules.

Two-socket tower and rack servers are the natural match. Boards listing the 240 normally accept the 242 with the same 82 W cooling. Troy 242 parts at 85 W need a BIOS with Troy support and different power tables, so the codename must be checked before swapping across generations.

Memory, PCIe and cooling

Memory is registered DDR with ECC per socket through the on-chip controller, reaching PC3200 on CG parts. Balanced DIMM populations per CPU give full bandwidth. Unbuffered desktop modules do not boot.

HyperTransport at 800 MHz links the CPUs to each other and to the chipset, while expansion hangs off the chipset. No PCIe lanes originate on the die. Cooling uses matched 82 W server heatsinks per socket with rack airflow. Both sockets need fresh paste and secure mounting for stable dual operation. DDR2 needs Socket F.

Upgrade paths

On Socket 940 the steps are the Opteron 244 at 1.8 GHz and the 246 at 2.0 GHz with the same socket and power class for two-socket boards. Troy 242 parts offer a 90 nm alternative with SSE3 where listed. Beyond Socket 940 a move to Socket F needs DDR2 boards. The 242 lifts with the lever, so swaps need no solder work.