AMD Opteron 6168 socket: Socket G34

What the Opteron 6168 is

The AMD Opteron 6168 is a 12 core Magny-Cours server processor that AMD released in March 2010 for 2S and 4S nodes. It runs 12 K10 cores at 1.9 GHz with no turbo, so 12 cores give 12 threads across two six core dies in one package. Each core carries 512 KB of L2 cache for 6 MB in total, backed by 2 by 6 MB of shared L3 cache for 12 MB. Power is rated at 115 W on a 45 nm process.

Magny-Cours is a multi-chip module with two dies linked by HyperTransport. The 6168 sits in the middle of the 12 core stack, above the 1.7 GHz 6164 HE at 85 W and below the 2.1 GHz 6172 at 115 W. Twelve threads at modest clocks suit virtualization hosts and integer servers where density beats peak speed. Four HyperTransport 3.1 links at 3.2 GHz tie sockets together for up to four sockets per node.

Memory is DDR3 ECC over four channels per socket, with registered DIMMs for large populations. There is no integrated graphics. The package uses 1944 lands in the 1974-contact G34 socket.

Socket and motherboard compatibility

The Opteron 6168 fits Socket G34 on SR5650, SR5670 and SR5690 boards with Magny-Cours firmware. The dual die package seats in the 1974-contact socket. Up to four sockets scale one node. Check the vendor stepping list before mixing with Interlagos or Abu Dhabi parts, which need newer firmware.

Registered ECC DIMMs populate four channels per socket. The socket SR5600 table covers this Magny-Cours codename as native. SP3 EPYC boards never accept Opteron silicon.

Memory, PCIe and cooling

Memory support is DDR3-1333 ECC over four channels per socket, with registered DIMMs up to large counts per node. Two channels feed each on package die, so balance DIMMs across sockets for NUMA fairness.

PCIe Gen 2 slots come from the SR5600 series chipset rather than the CPU. HyperTransport 3.1 links at 3.2 GHz carry die to die and socket to socket traffic.

Cooling uses vendor qualified server heatsinks for 115 W packages in 2S and 4S chassis on the board specific pattern. No retail mount exists. Airflow follows the chassis vendor specification.

Upgrade paths

On Socket G34 the upgrade is a faster Magny-Cours 12 core such as the 6176 at 2.3 GHz, or a move to Interlagos and Abu Dhabi generations with a BIOS update that lists them. Warsaw 12 and 16 core parts at 99 W cut power for cloud density.

A move beyond G34 needs a new platform. SP3 takes EPYC single die parts with DDR4 and many more cores. Keep the 6168 where DDR3 hosts still pay, and change platform where core density pays for new boards.