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AMD's Strix Point: Zen 5 Hits Mobile

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Re: AMD's Strix Point: Zen 5 Hits Mobile

#181

Post by MobiusHorizons »

AnthonyMouse wrote: post #119
rafaelmn wrote: post #76

Earlier quoted context omitted.

MacBook Air is thin and fanless, so it can be done.

"Thin and fanless" aren't that hard, just use any low power CPU. But then people also want fast. Apple does this by buying out TSMC's capacity for the latest process nodes and then taking the performance/efficiency trade off in favor of efficiency, so they get something with similar performance and lower power consumption. But then they charge you $400 for $50 worth of RAM and solder it so you can't upgrade it yourse…

I know everyone on this site loves to hate on soldered ram, but my impression is most people don’t understand that soldered ram is not the same thing as regular ram modules. They are literally different memory chips (LPDDR vs DDR) . When built to a specific chip my understanding is you can design for tighter timings and higher bandwidth which is important for the gpu. The M1 shipped with very fast LPDDR4X running at 4266MT/s which was even pretty fast by XMP desktop speeds at the time (2020). There are real engineering advantages to soldered ram especially if the memory controller has need designed with to take advantage of it. I guess it is similar to how gpu memory configurations are specialized and not modular.

Re: AMD's Strix Point: Zen 5 Hits Mobile

#182

Post by HenryCase »

sofixa wrote: post #94
Filligree wrote: post #18

Earlier quoted context omitted.

Ryzen mobile is consistently close, yeah. But with the sole exception of the Steam deck, I've yet to see a Ryzen mobile-bearing laptop, Windows included, which is close to the overall performance of the Macbook.

Depends on what you mean by "overall performance", but my Asus ROG Zephyrus G14 2023 is full AMD, and outperforms my work issued top of the line M1 MacBook Pro from a few months earlier in every task I've done across the two (gaming, compiling, heavy browsing). Battery life is lower under heavy load and high performance on the Zephyrus, but in power saving mode it's roughly comparable, albeit still worse.

[dead]

Re: AMD's Strix Point: Zen 5 Hits Mobile

#183

Post by Wytwwww »

aurareturn wrote: post #97
AnthonyMouse wrote: post #88

Earlier quoted context omitted.

> 1. ARM is inherently more efficient than x86 CPUs in most tasks > 2. Nuvia and Apple are better CPU designers than AMD and Intel The third possibility is that they just pick a different point on the efficiency curve. You can double power consumption in exchange for a few percent higher performance, double it again for an even smaller increase. The max turbo on the i9 14900KS is 253 W. The power efficiency is bad .…

>The third possibility is that they just pick a different point on the efficiency curve. You can double power consumption in exchange for a few percent higher performance, double it again for an even smaller increase. This only makes sense if the Zen5 is actually faster in ST than the M3. In this case, the M3 is 1.24x faster and 3.4x more efficient in ST than Zen5. AMD's Zen5 chip is just straight up slower in any cu…

> An M3 Max will often match a 14900KS in performance using 5-10% of the power.

On Cinebench and Passmark CPU the 14900K is 50-60% faster so I'm not sure that's true.

Re: AMD's Strix Point: Zen 5 Hits Mobile

#184

Post by devbent »

jwells89 wrote: post #152
jml7c5 wrote: post #56

I sit firm in my belief that the best thing Microsoft could do for their laptop ecosystem is to add support for a "max fan speed" slider somewhere prominent in the Windows UI. People want the option to make their laptop silent or nearly silent. And when users do need the power, they generally prefer a slightly slower laptop at a reasonable volume rather than the roar of a jet engine. Laptop manufacturers want their d…

It might also be good to mandate 10+ hours of battery life when the laptop is in power saving mode. A number of laptops that'd otherwise have decent battery life are hampered by things like half-baked power management of discrete GPUs that doesn't completely cut power supply to those components. Manufacturers should be more heavily testing under this mode.

A few misbehaving CSS filters can make my discreet GPU turn on and at that point my battery life is a goner. Not sure who to blame in that scenario.

There was an old bug in FF around 2018 where a tab using a GPU would prevent a Windows laptop from ever sleeping. That ended up destroying that laptop's battery after it got thrown in my backpack and overheated a couple times.

Re: AMD's Strix Point: Zen 5 Hits Mobile

#185

Post by jwells89 »

devbent wrote: post #184
jwells89 wrote: post #152

Earlier quoted context omitted.

It might also be good to mandate 10+ hours of battery life when the laptop is in power saving mode. A number of laptops that'd otherwise have decent battery life are hampered by things like half-baked power management of discrete GPUs that doesn't completely cut power supply to those components. Manufacturers should be more heavily testing under this mode.

A few misbehaving CSS filters can make my discreet GPU turn on and at that point my battery life is a goner. Not sure who to blame in that scenario. There was an old bug in FF around 2018 where a tab using a GPU would prevent a Windows laptop from ever sleeping. That ended up destroying that laptop's battery after it got thrown in my backpack and overheated a couple times.

Seems like this could be fixed by a system setting that disables automatic graphic switching which can be controlled by power profiles. That way the user can set the machine to use iGPU only when on battery, regardless of what programs want.

Re: AMD's Strix Point: Zen 5 Hits Mobile

#186

Post by atq2119 »

hajile wrote: post #61
cyp0633 wrote: post #51

Earlier quoted context omitted.

Power efficiency is a curve, and Apple may have its own reason not to make M1 Pro run at 110W as well

I stacked the deck in AMD's favor using a 3-year-old chip on an older node. Why is AMD using 3.6x more power than M1 to get just 32% higher performance while having 17% more cores? Why are AMD's cores nearly 2x the size despite being on a better node and having 3 more years to work on them? Why are Apple's scores the same on battery while AMD's scores drop dramatically? Apple does have a reason not to run at 120w --…

It's well known that performance doesn't scale linearly with power.

Benchmarking incentives on PC have long pushed X86 vendors to drive their CPUs at points of the power/performance curve that make their chips look less efficient than they really are. Laptop benchmarking has inherited that culture from desktop PC benchmarking to some extent. This is slowly changing, but Apple has never been subject to the same benchmarking pressures in the first place.

You'll see in reviews that Zen5 can be very efficient when operated in the right power range.

Re: AMD's Strix Point: Zen 5 Hits Mobile

#187

Post by atq2119 »

hajile wrote: post #54
dzaima wrote: post #45

Earlier quoted context omitted.

Some notes: 3: I don't think more decoders should be exponentially more complex, or even polynomial; I think O(n log n) should suffice. It just has a hilarious constant factor due to the lookup tables and logic needed, and that log factor also impacts the critical path length, i.e. pipeline length, i.e. mispredict penalty. Of note is that x86's variable-length instructions aren't even particularly good at code size.…

3. You can look up the papers released in the late 90s on the topic. If it was O(n log n), going bigger than 4 full decoders would be pretty easy. 6. Not all of those SIMD sets are compatible with each other. Some (eg, SSE4a) wound up casualties of the Intel v AMD war. It's so bad that the Intel AVX10 proposal is mostly about trying to unify their latest stuff into something more cohesive. If you try to code this stu…

The trend seems to be going towards multiple decoder complexes. Recent designs from AMD and Intel do this.

It makes sense to me: if the distance between branches is small, a 10-wide decode may be wasted anyway. Better to decode multiple basic blocks in parallel

Re: AMD's Strix Point: Zen 5 Hits Mobile

#188

Post by hajile »

dzaima wrote: post #171
hajile wrote: post #161

Earlier quoted context omitted.

Unlike x86, none of this is strictly necessary. As long as you put things back as expected, you may use all the registers however you like.

The option of not needing any fixed register usage would apply to, what, optimizing compilers without support for function calls (at least via passing arguments/results via registers)? That's a very tiny niche to use as an argument for having simplified compiler behavior. And good register allocation is still pretty important on RISC-V - using more registers, besides leading to less compressed instruction usage, mean…

Not just simpler basic allocation. There are fewer hazards to account for as well. The process on RISC-V should be shorter, faster, and with less risk that the chosen heuristics are bad in an edge case.

Re: AMD's Strix Point: Zen 5 Hits Mobile

#189

Post by hajile »

atq2119 wrote: post #186
hajile wrote: post #61

Earlier quoted context omitted.

I stacked the deck in AMD's favor using a 3-year-old chip on an older node. Why is AMD using 3.6x more power than M1 to get just 32% higher performance while having 17% more cores? Why are AMD's cores nearly 2x the size despite being on a better node and having 3 more years to work on them? Why are Apple's scores the same on battery while AMD's scores drop dramatically? Apple does have a reason not to run at 120w --…

It's well known that performance doesn't scale linearly with power. Benchmarking incentives on PC have long pushed X86 vendors to drive their CPUs at points of the power/performance curve that make their chips look less efficient than they really are. Laptop benchmarking has inherited that culture from desktop PC benchmarking to some extent. This is slowly changing, but Apple has never been subject to the same benchm…

Zen5 can be more efficient at lower clockspeeds, but then it loses badly to Apple's chips in raw performance.

Re: AMD's Strix Point: Zen 5 Hits Mobile

#190

Post by wiseowise »

mkhalil wrote: post #154
automatic6131 wrote: post #153

Earlier quoted context omitted.

>I sit firm in my belief that the best thing Microsoft could do for their laptop ecosystem is to add support for a "max fan speed" slider somewhere prominent in the Windows UI Until then, there's https://github.com/Rem0o/FanControl.Releases

A closed source application for controlling one's fan...umm no thank you. I never will understand the reasoning behind why people are so afraid of releasing their source code. Looks like a weekend project; does he expect to make a living out of a weekend project?

> Looks like a weekend project; does he expect to make a living out of a weekend project?

Why won’t you spend a weekend and do the world a service?

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