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Historically, though, focusing on performance per watt is a technique that hardware companies use to distract from otherwise not very impressive concrete perfor
by jchw 3y ago
Historically, though, focusing on performance per watt is a technique that hardware companies use to distract from otherwise not very impressive concrete performance improvements. You'd expect a new process node and chip shrink to bring modest performance per watt improvements even with largely identical designs. When it comes to GPUs, this has been combined with actually increasing the power draw to make the generational performance improvement look more impressive; so technically, performance per watt would improve, but the footprint would still increase, and yet the performance improvement would still be rather lackluster for any given price bracket. (This especially because you're competing with last generation's current street prices and used prices: if I can get a used M2 machine that's competitive in performance to a new M3 machine in the same price bracket, it might be more worthwhile.)
That's not to say there's no value in focusing on energy efficiency, especially for laptop chips; Apple Silicon was leagues ahead in energy efficiency when it launched, even if the gap is a lot smaller with newer Ryzen mobile chipsets. And speaking of Ryzen, the 5950X is a paragon of performance-per-watt in a desktop chip, which is of course still just as great as it makes it easier to power, cool and overclock. It's more to say that a shift toward focusing on energy efficiency could signal that they may be hitting road blocks in unlocking substantial performance improvements through better chip design alone, which of course makes sense, as its not like you can just linearly come up with design improvements every year forever, and they already came out swinging with their first generation chips.
- AnthonyMouse 3y agoThe other point here is that "performance per watt" is how you get "performance" when single-thread performance is hard, because it lets you fit more cores into the same TDP. The top end EPYC 9754 that will stomp basically anything has a 360W TDP but that's for 128 cores, which is less than 3W/core. The trouble for Apple is that although you can do this, they're paying the highest bid for first access to TSMC's new process, and doubling the core count would have used that much more die area. Which might have delayed the release as it takes more time to build up stock. So now we're into this weirdness where they give you a 22 hour battery life (how often are people awake for that many hours straight?) but they're getting outperformed by the Ryzen 7000 HX line on the older generation process node because it has more cores.
- bitwize 3y ago> Historically, though, focusing on performance per watt is a technique that hardware companies use to distract from otherwise not very impressive concrete performance improvements. Before Apple came along and made people realize PPW is pretty damn important in the mobile/laptop space.
- jchw 3y agoIt's definitely something that at least vendors knew was important. However, ARM/AArch64 chips already decimated x86 in performance per watt even when x86 chips generally had a process advantage. But ARM laptops generally sucked. Yes, the battery life was excellent: even a crummy Samsung Series 5 Chromebook delivered pretty impressive battery life for its light weight and price. But the performance? Yeah it was shit. Good enough for a few tabs of Chrome and nothing more, honestly not so bad. But the calculus for phones definitely worked out in ARM's favor. But that's the thing. Sufficient performance per watt is very important. Improvements to performance per watt are rarely unwelcome. However... you can mislead people regarding generational improvements when touting performance per watt metrics. If the design didn't actually improve much, a new process node and pumping more power in can cover a bit. Pretty much every vendor does this at some point, and even if Apple isn't currently doing this, pivoting towards touting the efficiency improvements rather than the raw performance is not a good sign, especially considering that these chips go in desktops too, and Apple still has some ground to cover if it wants to compete fully with high end desktop CPUs from the PC market.
- m463 3y agoperf per watt is not new and it is not just marketing hype, it is the limiting factor for not only notebooks but desktop gpus and cpus. the envelope is power vs. heat vs. performance. increasing perf per watt will let you do more in that envelope, whether it is in a notebook with batteries, or in a desktop with giant coolers holding you back.