[kllrnohj]

But again it's not. TDP isn't a defined thing. There's no standard for it. It's literally a made up value by the SoC manufacturer, and in the case of laptops the laptop manufacturer even gets to fiddle with it.

That said in this case it is a small difference regardless. The 6850U's TDP per AMD's spec is 15W-28W. That's bang on the same as M2 basically. There's no 3x difference here. Unless there is because again TDP is a made up number with no formal definition.

[Retric]

I had assumed it was 3x simply because you didn't object to their figure.

This laptop actually uses 28W TDP, so TDP is 2x not 3x which is still significant in less than 60 seconds.

[hajile]

M1/M2 use around 20-22w MAX in CPU-only tests. AMD and Intel chips usually max out at around 50-60w real-world power.

That's hardly apples to apples..

[kllrnohj]

> AMD and Intel chips usually max out at around 50-60w real-world power.

That's a sweepingly broad claim that's not at all well supported. AMD & Intel both make CPUs that top out far below 50-60w real-world power and also top out far, far above 50-60W real-world power.

From a different review of the same CPU (didn't check if same laptop, could be though) "The Ryzen 7 PRO 6850U with the Linux 5.18 kernel had a 18.4 Watt average (or 16.6 Watt average with Linux 5.19 Git) while the Ryzen 7 PRO 5850U average on Linux 5.18 was up at 21.96 Watts." https://www.phoronix.com/review/amd-ryzen7-6850u/8

So no, this isn't a 50-60W real-world power CPU. That's the non-U SKUs.

But if this AMD was a 50-60W CPU that'd exactly prove my point that TDP is a stupid number to compare and you always, always have to look at actual power consumption used (which this M2 vs. 6850U didn't do because as noted briefly in the intro power monitoring of the M2 doesn't work on Asahi yet)

[hajile]

Here's the 4800U running in a tiny NUC at over 60w and the 5800U running at almost 52w. They absolutely DO hit very high real power usage.

TSMC N5 only offers 15% performance OR 30% lower power vs 7nm. Peak clocks on the 6850U are 10% higher than the 5xxx generation AND is on N6 instead of N5 which offers a significantly lower advantage than what I stated. N6 offers an 18% reduction in area vs N7 while N5 offers a 45% reduction in area, so you can do your math from there.

https://www.anandtech.com/show/16236/asrock-4x4-box4800u-ren...

https://www.notebookcheck.net/R7-5800U-vs-E-2186M-vs-R7-PRO-...

[kllrnohj]

Why are you using peek instead of average? The average power over the test is what matters, not the instantaneous spikes. And did you miss the whole "configurable TDP" thing? The OEM gets to change the power targets. They aren't fixed. Saying the 4800U in a NUC uses power X, therefore all 4800U's use power X is flat out wrong. That's not how it works, different usages will set different power limits.

[hajile]

> Saying the 4800U in a NUC uses power X, therefore all 4800U's use power X is flat out wrong.

If the TDP is only configurable up to 28w, but they're pulling almost 70w total system power (when there's simply no other real power users in the entire system), then there's a serious problem with their default "average" power usage not respecting TDP in any real way.

A lot of AMD laptops have historically dropped 30+% of their performance when you unplug them (a notable example would be the MS Surface 4s) so they can look better than they really are as reviewers tend to be lazy about this and test performance while plugged in then do a rundown test to push out a "review" within the couple day window they can still make ad money.

Comparing to other Zen 3 chips (I've gone into that elsewhere in this thread), top-binned EPYC uses 4-4.5w per core to do 2.45GHz base clocks (that's 32-36w for 8 cores at ~2.5GHz while they claim base clocks of 2.7GHz). If you lower that max TDP even further, those clocks go down even farther.

I disliked when Intel started going with TDP as a recommendation rather than a limit 15 years ago. I disliked when AMD followed suit so they wouldn't seem to be at a disadvantage (well, at less of a disadvantage as they were getting crushed at that time). I dislike the M2 Air which throttles back rather quickly.

The only good thing in recent times has been Intel's 12th gen adding a peak power consumption metric (no doubt because the difference between that and their normal TDP would have basically guaranteed a lawsuit).

> Why are you using peek instead of average?

Many (most) benchmarks are short-lived, but people infer long-term performance from these.

If a chip is getting N marks at 60w, long-term performance where power adjusts down to 30-40w isn't going to be anywhere close to that number.

M1/M2 when actively cooled can run at peak clocks/performance all the time. This means that performance expectations are in line with what reviews show. This is good for consumers (and they need to be more upfront about the air thermal throttling).