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Our PowerEdge R815 sample turned up with four AMD Opteron 6174s clocked at 2.2GHz, and a somewhat meek 64GB of RAM — which can thankfully be scaled up to a maximum 256GB across the 32 DIMM slots.
Code-named Magny-Cours, the Opteron 6000 series brings what AMD calls Direct Connect 2.0, fundamentally an architecture focused on increasing bandwidth between the memory and CPUs. HyperTransport (HT) 3.0 links from processors have been increased from three to four, RAM has gone quad-channel (sort of) and it's all helped along by HT Assist.
The new processors don't actually have all their cores on a single die — rather they've been split into two dies of either four or six cores, for an upper limit of 12 cores per package. Each die has 6MB L3 cache on board, two memory channels (so perhaps not so much quad-channel as dual-dual- channel) and four HT 3.0 links to connect to the other die in the package.
Zoom out to the CPU scale, and there's another four HT 3.0 links to keep the system connected. Only the CPUs connected to the dual SR5670 northbridges use all four links — the rest only use three, which regardless allow any CPU to talk to any other CPU in a 4P system.
Every CPU can talk directly to each other in a 4P system, thanks to possessing four HT 3.0 links
In the framework of the PowerEdge R815 all of this leads to a system that has strengths in virtualisation, but thanks to its 2U size could also pass as a generic server for small-business purposes.
The readouts aren't fantastically useful at this size — but that's an awful a lot of cores for the size of the box
So what exactly is inside Dell's PowerEdge R815? Let's take a photo tour around the 2U server to see what it offers.