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I think you're overstating the issues here; and it's necessary to take what you can get in hard-to-do comparisons like this. There are caveats: certainly. The
by emn13 4y ago
I think you're overstating the issues here; and it's necessary to take what you can get in hard-to-do comparisons like this. There are caveats: certainly.
The Ryzen chip's TDP is configurable between 15W and 28W, which would include the GPU (but I doubt most of these tests touch the GPU anyhow). There will be power usage differences, but the TDP difference won't be huge - most differences will be due to utilization differences, which might be large.
The RAM issue usually doesn't affect most benchmarks, but it's something to consider if there are odd outliers.
The CPU core count number represents the reality of these chips (but M2 has a 4+4 config, apparently?).
Using linux is likely far from ideal, but probably necessary for them to run such an extensive and mostly comparable set of benchmarks. It's a significant caveat, but for CPU-limited benchmarks it's hopefully merely of reasonably limited impact (on the order of 30% on average rather than 300%, say?). OS differences tend to be larger for I/O, GPU, and some niche things like context-switching benchmarks. Of course, the power scheduler stuff matters.
It's worth pointing out that phoronix itself (on different hardware and slightly older OS versions) looked at some linux vs. macos benchmarks: https://www.phoronix.com/review/apple-m1-linux-perf https://www.phoronix.com/review/apple-m1-linux-perf - and while there were a few unsurprising macos wins, there also were some (far fewer) linux wins.
I think the benchmark is very interesting for what it is. Despite limitations, it _is_ informative. You can't always get a shrinkwrapped answer to whatever question you really have; so extra data-points such as this are helpful.
You know what they say: there are lies, damn lies, and benchmarks. Or something like that; caveat lector anyhow.
- viraptor 4y ago> You know what they say: there are lies, damn lies, and benchmarks. Also, all benchmarks flawed, some are useful. This one is definitely useful.
- hajile 4y ago15-20w is never the peak TDP. They will actually hit as much as 50-60w with minimal GPU usage just from trying to hit that insane clockspeed. M1 maxed out at 22w according to Anandtech and the max shouldn't be too much different for the M2.
- kllrnohj 4y ago[citation needed]
- mkopec 4y agoThat's Intel's boost behavior, AMD is much more linear. My 4750U in performance mode never exceeds 25W and settles at 23W under sustained load.
- hajile 4y agoWhat device is that chip in and at what frequencies is it running (by number of cores in use)?
- mkopec 4y agoLenovo ThinkPad Gen1 AMD, Arch Linux, acpi platform_profile = performance When running stress-ng, measured with turbostat: - 4.18 GHz single thread consuming 9W - 3 GHz 16 threads consuming 25W, ramping down to 2.94 / 23W after a couple of seconds and when compiling Linux on 16 threads it stays at 2.85 GHz / 23W In performance mode it does run at 80 degC under sustained load, so usually when undocked I just leave it in balanced mode where it's capped at 20W short / 15W long Also worth noting is that in low-power mode (11W / 11W) it'll still hit max single core frequency possible.
- bnieuwen 4y agoActually Phoronix has power benchmarks for the ACPI power profiles[1]. Seems like a boost to ~28W or so with a long term average of 22-23W. (Note that this is SoC package power instead of the full laptop though, but that is pretty typical, so no idea what the 22W was for comparison.) [1] https://www.phoronix.com/review/ryzen7-6850u-acpi https://www.phoronix.com/review/ryzen7-6850u-acpi
- hajile 4y agoI don't believe those numbers. The 4800U hit north of 65w in a NUC device[0]. The 5800U hits 52w in a laptop[1]. AMD runs their chips hot. TSMC N6 is a 7nm++ node. The even more advanced 5nm node only offers either 15% performance increase OR 30% power reduction vs N7. The 6850 clocks 10% higher, so the power shouldn't be dropping AT ALL. The 6850H has an identical turbo clockspeed of 4.7GHz and a TDP of 45w with real-world power consumption according to other reviewers being north of 65w. The base clocks for these chips is 2.7 and 3.5GHz respectively. In the case that they really are getting those numbers, they are certainly only at base clockspeeds (2.7GHz) which raises the impossible question of how Zen 3 suddenly got such a huge performance per clock advantage going from desktop to mobile. The numbers simply do not add up. [0] https://www.anandtech.com/show/16236/asrock-4x4-box4800u-renoir-nuc-review/11 https://www.anandtech.com/show/16236/asrock-4x4-box4800u-ren... [1] https://www.notebookcheck.net/R7-5800U-vs-E-2186M-vs-R7-PRO-5875U_12976_9902_14365.247596.0.html https://www.notebookcheck.net/R7-5800U-vs-E-2186M-vs-R7-PRO-...
- pdpi 4y ago> Using linux is likely far from ideal, This is Phoronix. Using Linux is the whole point, that's their audience.
- emn13 4y agoYep; I know. But for most people interested in this comparison that's nevertheless likely to make the comparison less representative of their workloads. Hats off to phoronix; it's not meant as a criticism - just an expectation that the benchmark results may not satisfy everyone.
- hrocha1 4y agoFeels like it makes perfect sense to compare performance on the same system. Is someone going to switch systems for some minor performance gains? I really doubt that. Usually it's something else that motivates people to switch. That said people pick different manufactures for their next device all the time (at least in the Linux/Windows world) and having performance comparison for these devices on your favorite system helps you choose.
- paulmd 4y ago> The Ryzen chip's TDP is configurable between 15W and 28W, TDP isn't a relevant number since the Ryzens will exceed their "configured TDP" for an unlimited period of time. see, eg, Anandtech's Tiger Lake review where a "15W cTDP" Renoir chip pulls 23W, and it is allowed to sustain that boost for an unlimited period of time, going against Intel chips that actually obey the 15W configured sustained-power limits... https://images.anandtech.com/doci/16084/Power%20-%2015W%20Comp%20Agi.png https://images.anandtech.com/doci/16084/Power%20-%2015W%20Co... The relevant number for comparing Ryzen against Intel/Apple SKUs is what AMD calls the "PPT" which is their sustained-boost TDP. The "cTDP" number is basically pure marketing these days, nobody is running at base clocks outside of contrived scenarios. (the Intel boost TDP is allowed to exceed the rated TDP too, but they only allow it for a limited time, it's a "sprint" feature on their chips, where AMD has just turned it into their new sustained TDP number, with the advertised TDP being essentially fake for marketing purposes it's specified at base-clocks that nobody ever runs.)
- emn13 4y agoAs far as I understand it, it's up to the device manufacturer to pick the exact TDP. It's by design that some devices might structurally exceed the base cTDP. I don't know the figures for lenovo's thinkpad, which is why I quoted the full range AMD offers. And even then, TDP is just a long term target for the purposes of cooling - workload, implementation and environmental (i.e. temperature) details might leave two chips with identical TDPs to nevertheless consume vastly different amounts of energy. In any case, we simply don't know how much power these systems used under this load. The expectation certainly is that the AMD system used more, but it's not clear how much more.
- FullyFunctional 4y agoThe focus on _power_, as opposed to _energy_, always annoyed me. When I'm using a notebook away from home, what matters to me is how long I can keep working. Phoronix should have measured how long each notebook could run the benchmark suite sustained and scaled the benchmark results accordingly. updated wording.
- 4y ago