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 ESTCinebench R15 Single-Threaded Results
Cinebench will run the CPU up to 100% load for the duration of the test. As this is the single-threaded run, only one core will be active, which should in theory provide more headroom for that one core than when all cores (physical and virtual) are loaded. There is no burst workload here at all, and sustained single-threaded performance is the key for this test.
The Core i5 does exactly what would be expected for this benchmark. With just a single core loaded, the cooling system has no issues keeping the CPU from throttling. It maintains an extremely consistent CPU frequency during the run. This cannot be said of the two Core M-5Y71 devices though. The Dell Venue 11 Pro starts off with quite a high frequency, but as the temperature increases, the CPU drops in frequency to keep below the threshold of 90°C set on the SoC. At any opportunity, it increases its CPU frequency to try to increase performance, but generally that does not last for very long, and it ends up falling back down. The Yoga 3 Pro on the other hand, has a much lower allowed SoC temperature, with Lenovo locking in on 65°C as their maximum target temperature. This keeps the frequency down.
The ASUS Zenbook has an entirely flat CPU line though. The excellent heat dissipation of the chassis allows it to run for the duration of the benchmark with no throttling at all. It has to be noted though that the maximum CPU frequency is a quite a bit lower than the 5Y71 devices, topping out at 2.0 GHz versus 2.9 GHz for 5Y71. It would be very interesting to see how the UX305 would do with the faster CPU inside, and if it would run into throttling issues as well.
Looking at the average CPU frequency over the run shows that the i5 clearly has the most headroom, which is not surprising. Averages are only part of the story though, with both of the 5Y71 devices being able to jump past the 5Y10's frequency several times during the test.
Looking at temperatures, it's interesting to note that the Dell Venue 11 Pro has the top-tier Core M-5Y71, but it puts that processor in what is the smallest chassis and with a plastic exterior. Consequently it quickly loads up to its maximum temperature and stays there for the duration. The rest of the devices stay much cooler with just a single core loaded.
Here we have the actual benchmark results. On single-threaded workloads, the 5Y71 can and does outperform 5Y10. Despite the average CPU frequencies being lower on both 5Y71 devices, they had enough headroom when necessary to jump past the very consistent 5Y10. None of them can match the Core i5 in this test. It is actually very interesting that the highest scoring Core M in this test has the lowest average CPU frequency.
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serendip - Wednesday, April 8, 2015 - link
Maybe Intel made too many compromises and OEMs reached too far with their designs. On one hand a fast race to sleep is good, yet on the other hand, I'd rather be a slow and steady tortoise who finishes the race than a hare that turbos and sleeps frequently to prevent overheating. Device buyers don't care about TDP or poorly set skin temperature limits, they'll just swear off Core M products that give them throttled 600 MHz speeds instead of full power.boblozano - Wednesday, April 8, 2015 - link
Good point, though I tend to think it'll depend on the use cases. I went back to separate desktop(s) / laptop (rather than a single, uber-laptop) about a year ago. Consequently the laptop can be optimized for size / weight / mobility, for which a core-m device is helpful.jospoortvliet - Thursday, April 9, 2015 - link
Exactly the same here. I will do my video and image editing on my quad-core desktop anyway, so a core M is perfect: I need portability and battery life in a laptop, not raw performance. Intel made just the right chip for a customer like me here. Too bad that on the desktop side, where I would love an affordable six or eight core with a high tdp, they fail me.girishp - Monday, April 13, 2015 - link
I tried doing the same thing, but portability quickly triumphs any advantage of a powerful desktop, especially when a good powerful laptop can do most of what I need. I bought the 2nd gen Mac Book Air for my wife and it was good for her basic multimedia requirements (Photoshop, Final Cut Pro, etc.), but the latest Mac Book just isn't powerful enough for any of her needs.MrSpadge - Wednesday, April 8, 2015 - link
Turbo gives the system increased responsiveness under bursty loads, i.e. most everyday workloads. There's no good reason not to use the performance available and be a tortoise voluntarily. When the load is sustained over longer periods, Turbo automatically throttles back to what ever limit the OEM has set. Had you choosen the tortoise mode, you would have started at this point. With Turbo you don't loose any performance compared to this scenario, it just makes you reach the limit quicker. Turbo also autoamtically factors in things like "how many cores are loaded", "how stresful is this program in reality", "how good is the device cooling" and "how hot is the ambient" by simply measuring them empirically (power consumption & temperature). In fixed tortoise mode you'd have to predict all of them and assume the worst case, just like Intel & AMD did for the first dual and quad cores with low fixed frequencies.If Turbo results in "turbos and sleeps frequently to prevent overheating" it is simply set up badly, significantly worse than Turbo on Intel Desktop CPUs since a few years. Instead of sleeping to avoid overheating the turbo bin must gradually be lowered until a good steady state is reached.
MrSpadge - Wednesday, April 8, 2015 - link
Forgot to add: it would be really nice if there was a simple user control for their current preference of maximum performance vs. tolerated temperature. Win allows limiting a CPUs maximum performance state, but most users will never find this option in the advanced energy settings. A simple slider as a sidebar-like gadget could work well. Not only for Core-M, but also for regular laptops and desktops. Add one slider for each discrete GPU's power target.mkozakewich - Wednesday, April 8, 2015 - link
Also, MS removed that option in all their PCs with connected standby. You can still enable it through the registry, but regular users are even less likely to make use of that option. We need some sane defaults set so we can have separate "Low Power", "Balanced" and "Overdrive" modes. We won't care about skin temperature if we've chosen to use that temperature briefly and we have an option to turn it back down.soccerballtux - Wednesday, April 8, 2015 - link
the biggest problem is Windows packaging in tons of storage indexing that runs every time you log in, or letting services run around in the background and datamine (Facebook, Amazon Music re-scans every 10 minutes-- I mean seriously? might as sell me a phone with 100MB less of RAM if you're going to do that)The_Assimilator - Wednesday, April 8, 2015 - link
Because it's obviously Windows' fault that it runs services that you told it to install.lilmoe - Thursday, April 9, 2015 - link
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