4 ms·

I don't even think it's as cut and dry as all that. I have an M2 Macbook air (IE; fanless little thing) but it completely desicrates the memory of its predeces

by dijit 4y ago

I don't even think it's as cut and dry as all that. I have an M2 Macbook air (IE; fanless little thing) but it completely desicrates the memory of its predecessor (Precision 5520 w/ Xeon E3-1505m v6) which has a 45W TDP.. (IE. double and a bit). In single core it continues to readily beat my Theadripper 3970x workstation which has a 280W TDP... (more than 12x the TDP of the M2, though it definitely beats it in multi-core...) I think something else is at play here. Be it a terrible filesystem or (as mentioned in another comment: the use of efficiency cores for compilation).

sz4kerto 4y ago
New Ryzen CPUs behave extremely interestingly when you manually apply TDP limits. As I mentioned in a sibling post in this thread, my 7950X is TDP limited to 105 watts (from the 170 watts factory default), and it loses around 8%-10% performance under perfectly multithreaded loads (and nothing if only e.g. half the cores or less are utilised). It is also possible to limit it to 65 watts, at which you lose around 20% or so but that's still very-very fast. At 105 watts it's around as fast as an M1 Ultra, which draws ~ 60 watts if all cores are used. Significant difference, but not something that's a very big problem in workstations. The 7950X is also competitive when limited to 65 watts -- it's barely underperforms the M1 Ultra.
rsynnott 4y ago
I don't think it's an efficiency core thing. On ~the same machine (I have a smaller SSD, but otherwise identical): > time make -j real 0m8.716s user 0m29.786s sys 0m15.102s > time taskpolicy -c background make -j real 0m42.196s user 1m13.041s sys 0m30.957s (The latter command forces use of the efficiency cores, the former is allowed use everything) One thing that _is_ notable is that it isn't really managing great parallelism (particularly visible in the efficiency core one). (Only looking at the actual build, as IME autoconf has remained reassuringly slow for the last 20 years, in defiance of all progress in CPUs, so I'm not at all surprised by that one...)
mhh__ 4y ago
A threadripper isn't a single thread monster, M1 should smash it (and does)
zamalek 4y ago
> Theadripper 3970x workstation which has a 280W TDP Is your RAM running at 3600MT/s (i.e. IF @ 1800MHz)? If not, that's 30% loss for some workloads. Also, compilation is a multi-threaded process. It doesn't make sense to blame things on single core perf.

by dijit 4y ago

sz4kerto 4y ago

New Ryzen CPUs behave extremely interestingly when you manually apply TDP limits. As I mentioned in a sibling post in this thread, my 7950X is TDP limited to 105 watts (from the 170 watts factory default), and it loses around 8%-10% performance under perfectly multithreaded loads (and nothing if only e.g. half the cores or less are utilised). It is also possible to limit it to 65 watts, at which you lose around 20% or so but that's still very-very fast. At 105 watts it's around as fast as an M1 Ultra, which draws ~ 60 watts if all cores are used. Significant difference, but not something that's a very big problem in workstations. The 7950X is also competitive when limited to 65 watts -- it's barely underperforms the M1 Ultra.

rsynnott 4y ago

I don't think it's an efficiency core thing. On ~the same machine (I have a smaller SSD, but otherwise identical): > time make -j real 0m8.716s user 0m29.786s sys 0m15.102s > time taskpolicy -c background make -j real 0m42.196s user 1m13.041s sys 0m30.957s (The latter command forces use of the efficiency cores, the former is allowed use everything) One thing that _is_ notable is that it isn't really managing great parallelism (particularly visible in the efficiency core one). (Only looking at the actual build, as IME autoconf has remained reassuringly slow for the last 20 years, in defiance of all progress in CPUs, so I'm not at all surprised by that one...)

mhh__ 4y ago

A threadripper isn't a single thread monster, M1 should smash it (and does)

zamalek 4y ago

> Theadripper 3970x workstation which has a 280W TDP Is your RAM running at 3600MT/s (i.e. IF @ 1800MHz)? If not, that's 30% loss for some workloads. Also, compilation is a multi-threaded process. It doesn't make sense to blame things on single core perf.