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Xiao_Xi

macrumors 68000
Oct 27, 2021
1,627
1,101
Interesting aside on this thread - I saw this in a WSJ article about Arm (paywalled, but the link is: https://www.wsj.com/articles/arm-based-chips-make-inroads-with-apple-amazon-11674436002)

In 2021, AMD CEO Lisa Su was quoted:
I think AMD has a lot of experience with the ARM architecture. We have done quite a bit of design in our history with ARM as well. We actually consider ARM as a partner in many respects.
From an AMD standpoint, we consider ourselves sort of the high-performance computing solution working with our customers, and that that is certainly the way we look at this. And if it means ARM for certain customers, we would certainly consider something in that realm as well.

AMD is looking at Arm? For video game consoles?
Or maybe RISC-V. It seems that AMD, like Nvdia, could use RISC-V in its GPUs.
 

pshufd

macrumors G4
Oct 24, 2013
10,146
14,572
New Hampshire
I wonder how much power it pulled to get that score.

I think that base was 3,300 Mhz and peak was 5,100 Mhz so the turbo speed might be a lot higher than the rating as is typical for measuring chip power consumption. I typically run my systems at 10% - 30% CPU usage the vast majority of the time so this could mean much better battery life for casual use. I'd guess that you'd have fans spinning loudly if you really cranked it up though.
 

leman

macrumors Core
Oct 14, 2008
19,521
19,674
I wonder how much power it pulled to get that score.

Probably 40-50 watts. But Zen4 has very good efficiency and performs admirably at low power draw. I’d expect these U-series to perform similar to M1 at comparable power draw, mostly because AMD can afford a more advantageous clocks due to their number of cores advantage.
 

Sydde

macrumors 68030
Aug 17, 2009
2,563
7,061
IOKWARDI
When you make a fair comparison – an M1 Max at N5 (the same process), the 7000 looks somewhere between pretty good and OK. The Max has a slightly lower SC score (around 3% lower, at about 35% lower clock, since we can prettymuch count on the 7000 running at Turbo for SC) and a slightly higher MC score (around 7% higher, running 10 threads on 2E/8P, vs the Ryzen running 16 threads on 8 cores).

This is as close as we have gotten so far to being able to compare high-performance ARM to x86-64 on the same fab process. AMD seems to have done a darn fine job with it, but I think Apple's processors still have a lead here.
 
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pshufd

macrumors G4
Oct 24, 2013
10,146
14,572
New Hampshire
When you make a fair comparison – an M1 Max at N5 (the same process), the 7000 looks somewhere between pretty good and OK. The Max has a slightly lower SC score (around 3% lower, at about 35% lower clock, since we can prettymuch count on the 7000 running at Turbo for SC) and a slightly higher MC score (around 7% higher, running 10 threads on 2E/8P, vs the Ryzen running 16 threads on 8 cores).

This is as close as we have gotten so far to being able to compare high-performance ARM to x86-64 on the same fab process. AMD seems to have done a darn fine job with it, but I think Apple's processors still have a lead here.

I heard that Intel's earnings were terrible this week even though I thought that they were winning back marketshare with discounting.

I like the idea of laptops that run cool with a light to medium workload as most people don't require high performance from laptops and these new AMD chips look pretty attractive for Windows laptops.
 

Xiao_Xi

macrumors 68000
Oct 27, 2021
1,627
1,101
The comparison of M2 and 7840U results is fascinating. M2 scores some big wins (Navigation, Clang, Object Remover, Photo Filter and Structure from Motion), but so does 7840U (Photo Library, Object Detection and Ray Tracer). The strangest result is Photo Filter because 7840U wins on multicore by a wider margin than other benchmarks, yet loses by a lot on single core.

I can understand 7840U winning when the benchmark uses SIMD instructions, but what explains M2 winning?

 

leman

macrumors Core
Oct 14, 2008
19,521
19,674
The comparison of M2 and 7840U results is fascinating. M2 scores some big wins (Navigation, Clang, Object Remover, Photo Filter and Structure from Motion), but so does 7840U (Photo Library, Object Detection and Ray Tracer). The strangest result is Photo Filter because 7840U wins on multicore by a wider margin than other benchmarks, yet loses by a lot on single core.

I can understand 7840U winning when the benchmark uses SIMD instructions, but what explains M2 winning?


M2 is a faster CPU, 7840U has more cores and can operate them at higher clock for brief periods of time.
 

Xiao_Xi

macrumors 68000
Oct 27, 2021
1,627
1,101
M2 is a faster CPU, 7840U has more cores and can operate them at higher clock for brief periods of time.
That doesn't explain the strange results. For example, M2 loses in the single-core Object Detection test, but wins with multiple cores.
 

Sydde

macrumors 68030
Aug 17, 2009
2,563
7,061
IOKWARDI
I can understand 7840U winning when the benchmark uses SIMD instructions, but what explains M2 winning?

MacBook Air (2022) vs LENOVO 21JVESIT10 - Geekbench Browser

Did you notice this?

IMG_3357.jpeg

The Lenovo has eight times as much RAM.
 
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Xiao_Xi

macrumors 68000
Oct 27, 2021
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The Lenovo has eight times as much RAM.
It appears that M2 results are independent of the amount of RAM.

One of the big wins of M2 is Navigation. According to the documentation, the Navigation test uses Dijkstra's algorithm.
This workload uses Dijkstra's algorithm to calculate 24 different routes on two OpenStreetMap maps — one for a small city (Waterloo, Ontario) and one for a large city (Toronto, Ontario).
Geekbench 6 CPU Workloads https://www.geekbench.com/doc/geekbench6-cpu-workloads.pdf

What makes M2 so good in the Dijkstra's algorithm?
 

Sydde

macrumors 68030
Aug 17, 2009
2,563
7,061
IOKWARDI
One of the big wins of M2 is Navigation. According to the documentation, the Navigation test uses Dijkstra's algorithm.

What makes M2 so good in the Dijkstra's algorithm?

Such a job would involve a whole lot of conditional branching, so perhaps Apple/ARM's branch prediction model is that much better, and branch prediction misses might also incur less of a penalty.
 
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Sydde

macrumors 68030
Aug 17, 2009
2,563
7,061
IOKWARDI
Well, this is fun


Ryzen's are exploding. Granted, it is probably a poorly designed motherboard, but still. This should not be happening.
 

diamond.g

macrumors G4
Mar 20, 2007
11,438
2,663
OBX
Well, this is fun


Ryzen's are exploding. Granted, it is probably a poorly designed motherboard, but still. This should not be happening.
It is just the X3D parts right (and even then is it just the 7800x3d)?
 

pshufd

macrumors G4
Oct 24, 2013
10,146
14,572
New Hampshire
Well, this is fun


Ryzen's are exploding. Granted, it is probably a poorly designed motherboard, but still. This should not be happening.

Those are high power parts; I doubt very much that these low power parts are affected by this problem and I've read that the actual numbers are pretty small. I love Gamers Nexus for breaking this stuff and then trying it out themselves.
 

Xiao_Xi

macrumors 68000
Oct 27, 2021
1,627
1,101
Golden Pig Upgrade has shared a review of the 7840HS, a chip that AMD rates with a TDP of 35-45W. Unfortunately, he used benchmarks useful for gaming.
AMD-Ryzen-7040-Phoenix-APUs-Power-Tests-_1-1456x551.png

 

Romain_H

macrumors 6502a
Sep 20, 2021
520
438
No, there are some non-X3D parts that have the problem too. I got this from Paul's Hardware this morning.
Bummer. Is there more info available yet as to what processors / which circumstances lead to mentioned meltdowns?
 

pshufd

macrumors G4
Oct 24, 2013
10,146
14,572
New Hampshire
Bummer. Is there more info available yet as to what processors / which circumstances lead to mentioned meltdowns?

Both shows indicated that this was not common. AMD has issued updates to the motherboard companies so they should be putting out updates to prevent this from happening in the future. Not really helpful for those that had this though.
 
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