[AnthonyMouse]

> I stacked the deck in AMD's favor using a 3-year-old chip on an older node.

You could just compare the ones that are actually on the same process node:

https://www.notebookcheck.net/R9-7945HX3D-vs-M2-Max_15073_14...

But then you would see an AMD CPU with a lower TDP getting higher benchmark results.

> Why is AMD using 3.6x more power than M1 to get just 32% higher performance while having 17% more cores?

Getting 32% higher performance from 17% more cores implies higher performance per core.

The power measurements that site uses are from the plug, which is highly variable to the point of uselessness because it takes into account every other component the OEM puts into the machine and random other factors like screen brightness, thermal solution and temperature targets (which affects fan speed which affects fan power consumption) etc. If you measure the wall power of a system with a discrete GPU that by itself has a TDP >100W and the system is drawing >100W, this tells you nothing about the efficiency of the CPU.

AMD's CPUs have internal power monitors and configurable power targets. At full load there is very little light between the configured TDP and what they actually use. This is basically required because the CPU has to be able to operate in a system that can't dissipate more heat than that, or one that can't supply more power.

> Meanwhile, if AMD used the same 33w, nobody would buy their chips because performance would be so incredibly bad.

33W is approximately what their mobile CPUs actually use. Also, even lower-configured TDP models exist and they're not that much slower, e.g. the 7840U has a base TDP of 15W vs. 35W for the 7840HS and the difference is a base clock of 3.3GHz instead of 3.8GHz.

[hajile]

> Getting 32% higher performance from 17% more cores implies higher performance per core.

I don't disagree that it is higher perf/core. It is simply MUCH worse perf/watt because they are forced to clock so high to achieve those results.

> The power measurements that site uses are from the plug, which is highly variable to the point of uselessness

They measure the HX370 using 119w with the screen off (using an external monitor). What on that motherboard would be using the remaining 85+W of power?

TDP is a suggestion, not a hard limit. Before thermal throttling, they will often exceed the TDP by a factor of 2x or more.

As to these specific benchmarks, the R9 7945HX3D you linked to used 187w while the M2 Max used 78w for CB R15. As to perf/watt, Cinebench before 2024 wasn't using NEON properly on ARM, but was using Intel's hyper-optimized libraries for x86. You should be looking at benchmarks without such a massive bias.

[AnthonyMouse]

> I don't disagree that it is higher perf/core. It is simply MUCH worse perf/watt because they are forced to clock so high to achieve those results.

The base clock for that CPU is nominally 2 GHz.

> They measure the HX370 using 119w with the screen off (using an external monitor). What on that motherboard would be using the remaining 85+W of power?

For the Asus ProArt P16 H7606WI? Probably the 115W RTX 4070.

> TDP is a suggestion, not a hard limit. Before thermal throttling, they will often exceed the TDP by a factor of 2x or more.

TDP is not really a suggestion. There are systems that can't dissipate more than a specific amount of heat and producing more than that could fry other components in the system even if the CPU itself isn't over-temperature yet, e.g. because the other components have a lower heat tolerance. There are also systems that can't supply more than a specific amount of power and if the CPU tried to non-trivially exceed that limit the system would crash.

The TDP is, however, configurable, including different values for boost. So if the OEM sets the value to the higher end of the range even though their cooling solution can't handle it, the CPU will start out there and gradually lower its power use as it becomes thermally limited. This is not the same as "TDP is a suggestion", it's just not quite as simple as a single number.

> As to these specific benchmarks, the R9 7945HX3D you linked to used 187w while the M2 Max used 78w for CB R15.

Which is the same site measuring power consumption at the plug on an arbitrary system with arbitrary other components drawing power. Are they even measuring it though the power brick and adding its conversion losses?

These CPUs have internal power meters. Doing it the way they're doing it is meaningless and unnecessary.

> You should be looking at benchmarks without such a massive bias.

Do you have one that compares the same CPUs on some representative set of tests and actually measures the power consumption of the CPU itself? Diligently-conducted benchmarks are unfortunately rare.

Note however that the same link shows the 7945HX3D also ahead in Blender, Geekbench ST and MT, Kraken, Octane, etc. It's consistently faster on the same process, and has a lower TDP.

[paulmd]

lmao he’s citing cinebench R15? Which isn’t just ancient but actually emulated on arm, of course.

Really digging through the vaults for that one.

Geekbench 6 is perfectly fine for that stuff. But that still shows apple tieing in MT and beating the pants off x86 in 1T efficiency.

x86 1T boosts being silly is where the real problem comes from. But if they don’t throw 30-35w at a single thread they lose horribly.

[AnthonyMouse]

> lmao he’s citing cinebench R15?

It's the only one where they measured the power use. I don't get to decide which tests they run. But if their method of measuring power use is going to be meaningless then the associated benchmark result might as well be too, right?

> Geekbench 6 is perfectly fine for that stuff. But that still shows apple tieing in MT and beating the pants off x86 in 1T efficiency.

It shows Apple behind by 8% in ST and 12% in MT with no power measurement for that test at all, but an Apple CPU with a higher TDP. Meanwhile the claim was that AMD hadn't even caught up on the same process, which isn't true.

> x86 1T boosts being silly is where the real problem comes from. But if they don’t throw 30-35w at a single thread they lose horribly.

They don't use 30-35W for a single thread on mobile CPUs. The average for the HX 370 from a set of mostly-threaded benchmarks was 20W when you actually measure the power consumption of the CPU:

https://www.phoronix.com/review/amd-ryzen-ai-9-hx-370/13

On single-threaded tests like PyBench the average was 10W:

https://www.phoronix.com/review/amd-ryzen-ai-9-hx-370/9

34W was the max across all tests, presumably the configured TDP for that system, derived from the tests like compiling LLVM that max out arbitrarily many cores.