Analyzing Intel Core M Performance: How 5Y10 can beat 5Y71 & the OEMs' Dilemma
by Brett Howse & Ian Cutress on April 8, 2015 8:00 AM ESTPCMark 8 Home Results
PCMark 8 Home is a much different workload than Cinebench. Cinebench thrives on sustained performance over the duration of the workload, with the CPU utilization staying around 100% for the duration. While an important metric, most people do not use their computers like that in their day to day lives, so Futuremark has crafted the PCMark suite to perform tasks which are more akin to what the average person will do in a day. Home includes workloads for web browsing, writing, gaming, photo editing, and video chat, and the nature of these loads mean that there is a lot more burst performance needed, so the race to sleep mentality of the Core M can be more effective in this scenario.
The burst nature of this benchmark is apparent just looking at the Core i5. No longer is the CPU frequency consistent across the board, and the temperatures ramp up and down as the work is performed and finished. Even more pronounced is the Dell tablet, which spikes up and down from its maximum temperature, but at the same time ramping clock speeds up quite high as well. The incredible cooling of the ASUS UX305 passive solution makes a big difference here, with the UX305 being able to maintain almost its maximum frequency for the duration of this benchmark. The Yoga 3 Pro really shines here though, with it maintaining quite high speeds for almost the entire duration of the benchmark.
Average CPU frequencies on the other hand show an unexpected disparity between the results we saw above and what the averages end up being. It's the cool Yoga 3 Pro that holds the highest average clockspeeds, followed by the UX305, and finally bringing up the rear is the Venure 11 Pro 7000.
The GPU averages for the three Core M devices are very similar overall, although none are at their maximum. Only the 15 watt Core i5 can maintain its maximum GPU frequency for the duration of this test. As we will see later, GPUs can draw a lot of power.
Moving on to temperature, with the burst nature of this benchmark, all of the devices have a reasonable time to cool off between workloads. The ASUS shows its amazing cooling capabilities again, with a significantly lower temperature than even both of the active cooled devices, but none of them are too close to their maximum allowed temperature over the duration.
Looking at the end result of this benchmark kind of throws everything we have seen in the above graphs on its head. The Yoga 3 Pro, despite sustaining a CPU frequency higher than all of the other Core M devices in this test, ends up scoring the worst, however the overall result by the Yoga 3 Pro is disadvantaged in this benchmark by the gaming test, due to the high resolution display on the Yoga 3 Pro. This is very similar to the results seen in the Dell XPS 13 review, where the QHD+ model only scored 2691 and the FHD model scored 3042 with the same processor. However the ASUS UX305 beats the other Core M devices, although it does so with a much lower resolution display than the Yoga 3 Pro which would certainly beat it otherwise.
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seapeople - Thursday, April 9, 2015 - link
Won't an over-aggressive turbo actually decrease performance? Processors are generally less power efficient at higher clock speeds, i.e., running at 3GHz is twice as fast as 1.5GHz but generally uses more than 2x the power, and thus more than 2x the heat.In this case, therefore, a processor that races to 3GHz will quickly (and less efficiently) use up its thermal headroom and have to throttle back moreso than a processor that stayed at 2GHz.
It's like a footrace - if the race is 100m long, you're going to finish fastest if you go all out. However, if the race is a mile long, then the guy who starts off sprinting is going to be sputtering along a quarter of the way into the race as the joggers pass him up.
MrSpadge - Friday, April 10, 2015 - link
You are right that with agressive Turbo the chip is running in a less power efficient state initially and will have to throttle a bit earlier than a slower, steadily running chip. but if we're talking about low performance under sustained loads, this doesn't matter: it affects the first few seconds, or 10's of seconds at most, whereas in the following minutes both systems are running at the same power efficient throttled speed, which is basically determined by the system cooling. It's not like the sprinter who's completely exhausted and can't recover.retrospooty - Wednesday, April 8, 2015 - link
I dont think its really all that complicated... If you are looking for raw performance, Core M isnt for you. It is really for low power devices that do basic stuff like browsing, email etc. For that purpose, its one hell of a CPU. That performance level at 4.5 watts is a hefty accomplishment IMOYuLeven - Wednesday, April 8, 2015 - link
I do development on a Core M machine. Instead of carrying 4 pounds of computing power on my back, I let a cloud based development box do the heavy lifting. The plume light Core M notebook is used basically to write the code and give orders to the Dev box. IMHO opinion a far better setup than having scoliosis for the sake of running code locally.mkozakewich - Wednesday, April 8, 2015 - link
It's not for web browsing. That's what Atom is for. A Core-M device is good for all regular core tasks except sustained graphics tasks. I wouldn't get one to game, but it'll be great for anything else.retrospooty - Thursday, April 9, 2015 - link
That is pretty much exactly what am saying. Basic use, core M is fine. Not for high performance requirements.nathanddrews - Wednesday, April 8, 2015 - link
They have taken the exact opposite approach to their SSD design, where they try very hard to offer constant and consistent performance.xthetenth - Wednesday, April 8, 2015 - link
Both make sense from the perspective of increasing perceived speed. With storage, it hanging and being slow is the biggest way it can impact the feel of the device, while processors that trade finishing short tasks much faster for a tiny decrease in how fast they complete long tasks do a lot to achieve a responsive feel.xthetenth - Wednesday, April 8, 2015 - link
Device buyers don't buy devices to get a higher average frequency, they buy things to do what they want without the device holding them up. Look at the benchmarks where the ASUS holds higher average frequencies but the Yoga's higher maximum frequency means it completes tasks faster, and it performs better in the benchmark. That sort of responsiveness is what turbo is for. The time to complete long tasks isn't going to be materially changed but the time to complete short tasks is going to be reduced significantly if the processor can use a quick burst like turbo allows.I'm also pretty sure that most users consider not getting burned by their device a good thing that should continue, incidentally.
StormyParis - Wednesday, April 8, 2015 - link
That's not a real use case though. Real use case is load a page (low CPU), render page (high CPU) read page (low CPU). I don't care how fast my CPU is idling while I'm reading the page, I do care how fast the page renders. It'd be different if I were running simulations.. that's what desktop CPUs are for.