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It uses more power. The decoder is like another ALU that is always screaming at 100%. It means you can easily keep up with ARM in speed but not power efficienc
by api 3y ago
It uses more power. The decoder is like another ALU that is always screaming at 100%. It means you can easily keep up with ARM in speed but not power efficiency.
- jeffbee 3y agoIt doesn't seem to matter in practice. Current generation Intel CPUs and the Apple M2 have very similar performance at the same power levels.
- rowanG077 3y agoHow did you arrive at that conclusion? Comparing the M2 Max vs 13650HX it's very obvious the M2 Max uses a LOT less power. It's not even close, it's less then HALF the power. The M2 max has a little worse performance. But it manages to beat the Intel in some benchmarks.
- jeffbee 3y agoYou don't have to let the Intel chips scale up the power like that. You can lock them to whatever power level suits you. An i7-1370P configured at 20W has broadly similar performance to an M2.
- rowanG077 3y agoMind linking me some power measurements at same wattage? I didn't even know you could set a power target on Intel or Appl Mx. Well you can disable turbo boost on Intel but even then intel blows over their own marketed TDP by a lot.
- jeffbee 3y agoIntel introduced the "running average power limit" over ten years ago. https://lkml.indiana.edu/hypermail/linux/kernel/1304.0/01322.html https://lkml.indiana.edu/hypermail/linux/kernel/1304.0/01322...
- rowanG077 3y agoRapl doesn't allow setting a limit which is always obeyed. You can set PL1 and PL2 limits. But intel CPUs will gladly go over those limits in the short term. For example when running a benchmark. That's why I asked for specific benchmarks which include power measurements. For example: https://www.notebookcheck.net/i7-1360P-vs-M2_14731_14521.247596.0.html https://www.notebookcheck.net/i7-1360P-vs-M2_14731_14521.247... this shows the M2 has a little worse performance compared to the 1360P. But the 1360P requires 2.5x the power to achieve that.
- Panzer04 3y agoApple’s chips are on better process nodes, which confuses the issue. That being said, you really have to test chips at the same power level to get an idea of performance per watt in a comparison. You can easily double CPU power for only a few hundred MHz or 10-20% extra performance. See https://www.pcworld.com/article/1359352/cool-down-a-deep-dive-into-13900k-power-use-and-efficiency.html https://www.pcworld.com/article/1359352/cool-down-a-deep-div..., which benchmarks chips at different power limits for an example.
- rowanG077 3y agoYes I agree with you. That doesn't mean this is easy to achieve. With the exception of AMD chips it's unfortunately very hard to simply "benchmark with a fixed power budget".
- jeffbee 3y agoYour model of RAPL's abilities is too limited. "PL1/PL2" is a thing that youtube reviewers have figured out, but it is a part of a larger picture. It does not make sense to discuss them without also discussing the time parameters. RAPL is able to hard-cap the (estimated) peak power consumption. If it lacked this feature, operating them at warehouse scale would be impossible.
- arp242 3y agoHow much power does it (roughly) use? Are we talking about 1% of the overall usage? 10%? 50%?
- tester756 3y agothis article states different, so how is it?
- deleted 3y ago[deleted]