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I don't understand why people keep talking about power performance per watt, do we know for a fact that a 90w Apple GPU would perform 4x faster if it was runnin
by Thaxll 5y ago
I don't understand why people keep talking about power performance per watt, do we know for a fact that a 90w Apple GPU would perform 4x faster if it was running at 500w? Does the performance scales linearly?
The other thing is price, the m1 max cost $5k here. You know what kind of PC you can get for that price? A 3080 MSRP is $700 and beat any mac GPU right ( and that's a GPU from last year ). 5900x cost $480.
- JohnBooty 5y agoThe obvious answer is that performance/watt is literally everything when talking about laptops. Most people favor laptops these days even if they (like me) leave their machines "docked" 90% of the time. do we know for a fact that a 90w Apple GPU would perform 4x faster if it was running at 500w It's somewhat besides the point IMO, but don't GPU workloads tend to scale well simply by adding more compute units? This should be pretty easy to extrapolate by comparing M1 / M1 Pro / M1 Max power consumption and performance relative to the # of GPU cores. I would certainly like to see Apple go nuts and make a true, cost-and-power-consumption-are-no-object world destroying GPU. If only as a halo product. But I wouldn't hold my breath.
- dboat 5y agoI think increasing cores/power limits just gets you up to some other bottleneck. At some point you are adding 90% more power use for 3% more performance.
- jayd16 5y agoPerformance/watt it not everything. It's not really even something. It's a derivative concern. The only reason I care about performance/watt is because I actually care about noise, heat and battery life. I'm not running a data center off a laptop so the cost benefits of performance/watt are not even a concern. Its a nice chip but we shouldn't confuse the marketing for the actual benefits. If a higher performance/watt but much lower absolute performance chip was released, I wouldn't be interested.
- emodendroket 5y ago> The only reason I care about performance/watt is because I actually care about noise, heat and battery life. Yeah, all pretty major concerns?
- jayd16 5y agoThe point is at best I care about perf/watt indirectly and the things I do care about can be improved in other ways so its incorrect to say perf/watt is everything. I admit it's a pedantic comment but I was pulled in by use of "literally everything".
- emodendroket 5y agoThe other ways to mitigate those things have pretty significant downsides. For instance, maybe you can stick a bigger battery in there to improve battery life, sure. But now it's heavier and more expensive.
- JohnBooty 5y agoThe point is at best I care about perf/watt indirectly and the things I do care about can be improved in other ways Not necessarily, at least not for single core performance. Even if you're willing to accept unbounded power consumption and waste heat, the die size of the CPU itself won't be increasing at the same rate. You fairly quickly learn that dissipating kilowatts of watts of heat from something as tiny as a CPU die (or, more accurately, one particular subset of functional units from in a CPU core) is awfully difficult. At some point, the CPU/GPU/etc need to be kept under a certain temp, which sets an upper bound on watts. So, no escaping watts/performance....
- rsynnott 5y ago> and the things I do care about can be improved in other ways so its incorrect to say perf/watt is everything. Okay, noise, _maybe_, but how are you proposing to improve heat and battery life without improving perf/watt? Your options for battery life are either to reduce performance, or to increase battery size (but, well, good luck with that; the 16" MBP is already as big as a laptop battery can practically be, as if it was any bigger you wouldn't be allowed take it on a plane). Your only option to reduce heat without improving perf/watt would be to reduce performance.
- rsanheim 5y agoOne reason: try to work alongside a 3080 or 3090 running at full power for awhile, and you will understand. Especially if you don't have really good AC in your work area during summer. =)
- ClumsyPilot 5y agoYou can downclock your GPU as much as you want and get better perf/watt, which is what most crypto miners do
- deleted 5y ago[deleted]
- jojobas 5y agoBut you only need like 12% of the power to match Apple?
- smoldesu 5y agoWhy would I run it at full power? I could have M1 Max-beating performance while staying well under 70, and modern Nvidia cards will happily idle around 30c when driving hi-res displays.
- emodendroket 5y agoBattery life, energy costs, waste heat... take your pick.
- tambourine_man 5y ago> Does the performance scales linearly? On GPUs, pretty much. It’s even called embarrassingly parallel for this reason.
- JohnBooty 5y agoAt some point you hit bandwidth limitations, right? Unless each core has local, dedicated memory they will need to access the GPU's shared memory for various things right?
- smoldesu 5y agoPCIe 4.0+ is capable of ~31504MB/s on an x16 interface. Besides that, you might run into memory issues, but I honestly haven't seen a memory-bottlenecked workload on GPUs outside of the crypto mining scene.
- ksec 5y ago>At some point you hit bandwidth limitations Yes, with HBM3 you could go up to 5TB/s and in the future 6.4TB/s. To give a comparison a 3980 RTX Ti has ~900 GB/s with GDDR6x. But just with everything we hit TDP or cost ceiling well before any technical barriers.
- ksec 5y ago>do we know for a fact that a 90w Apple GPU would perform 4x faster if it was running at 500w? Does the performance scales linearly? The answer is yes. Scaling with more cores running at the same frequency giving unlimited bandwidth. Yes it is pretty much linear for GPU. I guess that is why most of the discussions is so tiring. Because this fact is not known.