[AnthonyMouse]

The problem with Geekbench is it's trying to average the scores from many different benchmarks, but then if some of them are outliers (e.g. one CPU has hardware acceleration or some other unusual aptitude for that specific workload), it gets an outsized score which is then averaged in and skews the result even if it doesn't generalize.

What you want to do is look at the benchmarks for the thing you're actually using it for.

> they're 2-4x more power efficient as well.

This is generally untrue, people come to this conclusion by comparing mobile CPUs with desktop CPUs. CPU power consumption is non-linear with performance, so a large power budget lets you eek out a tiny bit more margin. For example, compare the 65W 5700X with the 105W 5800X. The 40 extra watts buys you around 2% more single thread performance, not because the 5700X has a more efficient design -- they're the exact same CPU with a different power cap. It's because turning up the clock speed a tiny bit uses a lot more power, but desktop CPUs do it anyway, because they don't have any such thing as battery life and people want the extra tiny bit more. Or the CPU simply won't clock any higher and doesn't even hit the rated TDP on single-threaded workloads.

The extra power will buy you a lot more on multi-threaded workloads, because then you get linear performance improvement with more power by adding more cores. But that's where the high core count CPUs will mop the floor with everything else -- while achieving higher performance per watt, because the individual cores are clocked lower and use less power.

[aurareturn]

  The problem with Geekbench is it's trying to average the scores from many different benchmarks, but then if some of them are outliers (e.g. one CPU has hardware acceleration or some other unusual aptitude for that specific workload), it gets an outsized score which is then averaged in and skews the result even if it doesn't generalize.

Geekbench CPU benchmark does not optimize for accelerators. It optimizes for instruction sets only.

[AnthonyMouse]

It's not just about coprocessors. If one CPU has a set of SIMD instructions that double performance on that benchmark or more, that creates a large outlier that significantly changes the average.

Apple Silicon also has more memory bandwidth the primary purpose of which is to feed the GPU because most CPU workloads don't care about that, but if you average in the occasional ones that does then you get more outliers.

Which is why the thing that matters is how it performs on the thing you actually want to run on it, not how it performs in aggregate on a bunch of other applications you don't use.

[KingOfCoders]

The max power on Intel/AMD CPUs is only there to get the CPU "performance crown". As you've said, you spend a large amount of additional power for very minor gains (to be at the top of fancy Youtube review charts).

It looks though as if AMD/Intel feel threatened by Snapdragon though - we'll see what AMD Strix / Halo brings for the first meaningful x86 mobile processor in years (or Luna Lake).

[AnthonyMouse]

> The max power on Intel/AMD CPUs is only there to get the CPU "performance crown".

It's mostly not. Its real purpose is to improve performance on threaded workloads.

Multi-core CPUs work like this: At the max boost a single core might use, say, 50 watts. So if you have 8 cores and wanted to run them all full out, you'd need a 400 watt power budget, which is a little nuts. It's not even worth it. Because you only have to clock them a little lower, say 4GHz instead of 5, to cut the power consumption more than in half, and then you get a TDP of e.g. 100W. Still not nothing but much more reasonable. You can also cut the clock speed even more and get the power consumption all the way down to 15W, but then you're down to 2GHz on threaded workloads and sacrificing quite a bit of multi-thread performance.

So they're not just trying to eek out a couple of percent, even though that's all you get from single thread improvement, because a single core was already near or at its limit. Whereas 8 cores at 4GHz will be legitimately twice as fast as the same cores at 2GHz. But they'll also use more than twice as much power. Which matters in a laptop but not so much in a desktop.

Of course, the thing that works even better is to have 16 cores or more that are clocked a little lower, which improves performance and performance per watt. The performance per watt of the 96-core Threadrippers are astonishingly good -- even though they're 360W. But that also requires more silicon, so those ones are the expensive ones.

[hajile]

Apple's M3 Max CPU cores peak out at 55w for 16 cores (12p+4e). AMD's 8-core U-series chips peak out at 65-70w on CPU-only workloads and still loses out massively in pretty much every category.

If you downclock that AMD chip, it does get more efficient, but also loses by even larger margins.

[AnthonyMouse]

Because you're comparing a 16-core CPU to an 8-core CPU on threaded workloads, which as mentioned is where the multi-threaded workloads will favor the one with more cores on both performance and performance per watt. But why not compare it to the Ryzen that also has 16 cores, like the 7945HX3D? Because then the Ryzen is generally faster on threaded workloads, even though the TDP is still 55W -- and even though it's on TSMC 5nm instead of 3nm.

[hajile]

Who said I was comparing multithreaded loads? AMD will hit that on just one core with those boost clocks.

[AnthonyMouse]

The U series doesn't even hit that power consumption when all cores are in use -- its power consumption is between 10 and 30W. The higher power mobile chips are the H series, but even there the one that uses "65-70W" is the 16-core 7945HX3D, which is a 5nm/6nm chip you're comparing to Apple's 3nm one, and even then it's almost as fast. Most of even the H series uses less power than that, partially because some of them are 4nm but mostly because they have fewer cores.

But you can't really expect an older CPU on a previous generation process node with lower power consumption to be faster.