4 ms·

Not to mention the fact that "pushing up to 700W underload" is.. absolutely nothing since that means, ignoring everything else and just assuming CPU drawing tha

by helf 4y ago

Not to mention the fact that "pushing up to 700W underload" is.. absolutely nothing since that means, ignoring everything else and just assuming CPU drawing that, the cores are only using 7w PER CORE. And this AMD system is using apparently a peak of 3.75w per core? really?

esperent 4y ago
This comment made me realize I've never seen power per core specified. That seems like a great metric. Would calculating this be as simple as dividing peak usage by the number of cores? (Ignoring that modern CPUs have multiple core types)
- toast0 4y ago
  Power per core is pretty variable though. If you've got a lightly threaded workload, you shouldn't be getting 40-52 cores per socket, but many of the cores could be at near 0w and some of the cores will use more power than they would on an all cores workload.
- helf 4y ago
  It wouldn’t really. I only used that because the parent poster was making it sound like total power draws with the cores all pegged out. And if they are actually doing work and not just running full bore through a whole lot of NOPs then that would be a sorta average of power on each core. But as the other commenter said, the actual per core usage will vary /wildly/ even under high load. You would half to run something fairly specialized such as prime95, which can run entirely from cache, to get more accurate per core wattage values under same load maximum load. As it stands, my i9-13900K seems to have an idle “package” draw of around 10-12w and can peak at 360w under prime95 load. And that’s stock. I can make it ramp way past 360W with very little effort. But under “normal” desktop usage it happily sits well under 100w. So… shrugs. I would like to know more on this parent’s setup instead of “My server with literally 40% of the core count uses 1/6 of the power!” But we may not be so lucky.
  - aetherspawn 4y ago
    The load case is not 1:1 and the experience is only anecdotal, but I put a few more details about the load in another comment below. My commentary is only really about what we believed about AMD before making our purchase (internet forums like this one warn about energy use), how that wasn't really the case when we measured it on a real load, and why we 'feel' we would prefer to go the smaller and cheaper AMD server route next time.
    - deleted 4y ago
      [deleted]

by helf 4y ago

esperent 4y ago

This comment made me realize I've never seen power per core specified. That seems like a great metric. Would calculating this be as simple as dividing peak usage by the number of cores? (Ignoring that modern CPUs have multiple core types)

toast0 4y ago
Power per core is pretty variable though. If you've got a lightly threaded workload, you shouldn't be getting 40-52 cores per socket, but many of the cores could be at near 0w and some of the cores will use more power than they would on an all cores workload.
helf 4y ago
It wouldn’t really. I only used that because the parent poster was making it sound like total power draws with the cores all pegged out. And if they are actually doing work and not just running full bore through a whole lot of NOPs then that would be a sorta average of power on each core. But as the other commenter said, the actual per core usage will vary /wildly/ even under high load. You would half to run something fairly specialized such as prime95, which can run entirely from cache, to get more accurate per core wattage values under same load maximum load. As it stands, my i9-13900K seems to have an idle “package” draw of around 10-12w and can peak at 360w under prime95 load. And that’s stock. I can make it ramp way past 360W with very little effort. But under “normal” desktop usage it happily sits well under 100w. So… shrugs. I would like to know more on this parent’s setup instead of “My server with literally 40% of the core count uses 1/6 of the power!” But we may not be so lucky.
- aetherspawn 4y ago
  The load case is not 1:1 and the experience is only anecdotal, but I put a few more details about the load in another comment below. My commentary is only really about what we believed about AMD before making our purchase (internet forums like this one warn about energy use), how that wasn't really the case when we measured it on a real load, and why we 'feel' we would prefer to go the smaller and cheaper AMD server route next time.
  - deleted 4y ago
    [deleted]