Announcement

Collapse
No announcement yet.

possibly strange cpu loading behaviour on 3990x.

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • possibly strange cpu loading behaviour on 3990x.

    this whole ryzen smart clock speed thingy is new to me, but im beginning to notice an odd trend.

    sometimes, when i render, and also when i run other benchmarks, i get an average clockspeed of 3-6 -3.8 and it hits the power limits ive set. (im using PBO with a limit around 400 watts) this is relatively expected behaviour. rendering is, obviously, nice and fast.


    however other times, or maybe other scenes (im just beginning to notice this, need to test better) when rendering, the cpu will clock all the way up to 4.25 ghz all core speed, show cpu loaded 100%, but, and this is the wierd part, use only 330 watts and stay relatively cool. i also have a sneaking suspicion its rendering slower than the normal speeds of 3.7 ghz with lots of watts being drawn.


    it basically seems like sometimes, vray is not loading the cpu properly, despite using all cores. so the cpu is clocking higher due to the light load. that would explain the suspiciously low power draw.

    -note, i actually tested this with PBO disabled too (stock for this cpu) on a scene exhibiting this behaviour.. a plane with fine displacement on. - it clocked all core to 4ghz, which is definitely not normal for a cpu which is supposed to hit 3.1 all core under heavy load..

    could anybody at Chaos suggest a reason for this? im not clever enough to understand how a cpu can have all cores going (at 100% according to windows) but be lightly loaded when rendering.

    Last edited by super gnu; 04-03-2020, 02:19 PM.
Working...
X