From: Norman Geist (norman.geist_at_uni-greifswald.de)
Date: Thu Jun 26 2014 - 00:59:13 CDT
> -----Ursprüngliche Nachricht-----
> Von: owner-namd-l_at_ks.uiuc.edu [mailto:owner-namd-l_at_ks.uiuc.edu] Im
> Auftrag von Kenno Vanommeslaeghe
> Gesendet: Mittwoch, 25. Juni 2014 17:26
> Cc: Namd Mailing List
> Betreff: Re: AW: namd-l: Xeon vs i7 and ECC vs SDRAM
>
> On 06/25/2014 01:31 AM, Norman Geist wrote:
> > Xeon is more expensive but also more reliable.
>
> I've never seen a single indication that the CPU itself is actually
> more
> reliable. In your comparison, the main advantages of the Xeon are:
> - multi-socket support (which you're not profiting from in a single
> socket
> configuration)
> - ECC support (which means that a Xeon will be more reliable *if and
> only
> if* it's paired with ECC memory). Also worth noting is that:
> * some i7 models do have ECC support
> * ECC memory typically has slower timings, though that may or may
> not
> impact real-life performance for any particular application. For a lot
> of
> applications, the impact is very small
> - bigger cache; on paper, that's good for performance for some
> applications, but for the specific purpose of trajectory analysis, it
> is
> quite likely you'll swamp the cache no matter how big it is, so then I
> wouldn't expect it to make much difference (though you'll never know
> for
> sure without benchmarking)
>
> > I wouldn't put my shirt on the i7 in this regards.
>
> Unless one buys a top-of-the-line i7 with very high TDP, running 24/7
> shouldn't be an issue.
It's not only about the CPU, but the workstation concept itself that can
make a difference regarding lifetime, reliability and administration
abilities. A consumer !!PC!! is _NOT_ build to run 24/7 and one might
painfully notice sooner or later. This can include the following problems:
- low cost parts (mostly cheap capacitors)
- power supply at output limit (really often)
- insufficient cooling (especially with some dust inside)
- lack of administration abilities (BIOS, BMC, MCE)
- no ECC
- no RAM cooling (usually)
- low cost heat sink paste (CPU's getting hotter with time)
- low quality material connectors (oxidation, weird hardware problems)
- limited support for expansion cards (Tesla, MIC, Infiniband)
- no warranty expansion, low warranty services
- no warranty for 24/7
Norman Geist.
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