Open Compute 'Group Hug' Board Allows Swappable CPUs In Servers 82
Nerval's Lobster writes "AMD, Intel, ARM: for years, their respective CPU architectures required separate sockets, separate motherboards, and in effect, separate servers. But no longer: Facebook and the Open Compute Summit have announced a common daughtercard specification that can link virtually any processor to the motherboard. AMD, Applied Micro, Intel, and Calxeda have already embraced the new board, dubbed 'Group Hug.' Hardware designs based on the technology will reportedly appear at the show. The Group Hug card will be connected via a simple x8 PCI Express connector to the main motherboard. But Frank Frankovsky, director of hardware design and supply chain operations at Facebook, also told an audience at the Summit that, while a standard has been provided, it may be some time before the real-world appearance of servers built on the technology."
Why? (Score:5, Informative)
Maybe this would be useful in some HPC environments where applications can be written to maximize the use of CPU cache, but the bandwidth of a PCI /8 or /16 slot is a fraction of what is available to a socketed CPU.
A core i7 has been clocked at 37GB/sec [anandtech.com] bandwidth, while PCIe /8 is good for 1.6GB/sec, and /16 is good for 3.2GB/sec
Is replacing the CPU socket with a PCIe card really worth giving up 90% of the memory bandwidth? I've never upgraded a CPU on a motherboard even when new generation CPU's are backwards compatible with the old motherboard since if I'm going to buy an expensive new CPU, I may as well spend the extra $75 and get a new motherboard to go along with it.
Likewise, by the time I'm ready to retire a 3 or 4 year old server in the datacenter, it's going to take more than a CPU upgrade to make it worth keeping.