Inside the S822L: Hardware Components

The 2U Rack-mount S822L server contains two IBM POWER8 DCM sockets. Each socket thus contains two cores connected by a 32GBps interconnect. The reason for using a Multi-Chip-Module (MCM) is pretty simple. Smaller five-to-six core dies are a lot cheaper to produce than the massive 650 mm² monolithic 12-core dies. As a result the latter are reserved for IBM's high-end (E880 and a like). So while most POWER8 presentations and news posts on the net talk about the multi-core die below...

... it is actually an MCM with two six core dies like the one below that is challenging the 10 to 18 core Xeons. The massive monolithic 10-12 core dies are in fact reserved for much more expensive IBM servers.

The layout of the S822L is well illustrated by the scheme inside the manual.

Each DCM offers 48 PCIe Gen 3 lanes. 32 of those lanes are directly connected to the processor while 16 connect to PCIe switches. The PCIe switches have "only" 8 lanes upstream to the DCM, but offer 24 lanes to "medium" speed devices downstream. As it unlikely that both your SAS controllers and your network controllers will gobble up the full PCIe x8 bandwidth, this is a very elegant way to offer additional PCIe lanes.

Taking a Closer Look Inside IBM's S822L The L4-cache and Memory Subsystem
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  • Mondozai - Friday, November 6, 2015 - link

    That's too bad. Over 90% of the world population exists outside of it and even if you look at the HPC market, the vast majority of that is, too.

    The world doesn't revolve around you. Get out of your bubble.
  • bji - Friday, November 6, 2015 - link

    He never claimed the world revolved around him, he just made a true statement that may be worth consideration. Your response is unnecessarily hostile and annoying.

    I would expand Jtaylor1986's statement: I believe that most if not all native English speaking populations use commas for thousands grouping in numbers. Since this site is written in English, it might be worthwhile to stick to conventions of native English speakers.

    It's possible that there are many more non-native English speakers reading this site who would prefer dots instead of commas, but I doubt it. Only the site maintainers would know though.
  • Jtaylor1986 - Friday, November 6, 2015 - link

    You read my mind :)
  • mapesdhs - Tuesday, November 10, 2015 - link

    Talking to numerous people around Europe about tech stuff, I can't think of any nation from which someone used the decimal point in their emails instead of a comma in this context. I'd assumed the comma was standard for thousands groupings. So which non-US countries do use the point instead? Anyone know?
  • lmcd - Friday, November 6, 2015 - link

    Cool on the rest of the world part, but the period vs comma as delimiters in the world numeric system ARE backward. In language (universal, or nearly), a comma is used to denote a pause or minor break, and a period is used to denote the end of a complete thought or section. Applied to numerics, and you end up with the American way of doing it.

    ^my take
  • JohanAnandtech - Saturday, November 7, 2015 - link

    Just for the record, this was not an attempt to nag the US people. Just the mighty force of habit.
  • ZeDestructor - Saturday, November 7, 2015 - link

    For future use: just use a space for thousands seperation (that's how I do it on anything that isn't limited to a 7seg-style display), and confuse readers by mixing commas and periods for decimals :P
  • tygrus - Sunday, November 8, 2015 - link

    I like to use a fullstop for the decimal point, an apostrophe for the thousands separator, a comma for separating items in the list, don't start a sentance with a digit.
    One list of numbers may be : 3'500'000, 45.08, 12'500.8, 9'500. Second list : 45'000, 15'000, 25'000. We use apostrophes when we contract words like don't so why not use it for contracting numbers where we would otherwise have the words thousand, millions, billions etc ?
  • mapesdhs - Tuesday, November 10, 2015 - link

    I have a headache in my eyeballs! :D
  • ws3 - Friday, November 6, 2015 - link

    North America is on the majority side on this issue. Asia, in particular, is almost completely on the side of using a dot as the decimal separator and a comma to put breaks in long numbers.

    Get with the program Europe. The world doesn't revolve around you!

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