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 EST3DMark Sky Diver Results
Most of the previous benchmarks were day to day tasks. Some involved the GPU, but it was never the focus. We will now move on to benchmarks which focus on GPU performance to see what kind of an effect this can have. Remember, the TDP of Core M is 4.5 watts including the integrated graphics, so any thermal room needed for graphics is going to come at the expense of the CPU. 3DMark Sky Diver is aimed for gaming laptops and mid-range PCs, so it is a bit too much load for integrated graphics. But it does feature DirectX 11 and includes both graphics and physics tests. The benchmark is around five minutes long.
We can see that the Core i5 continues shrugging off these tests. While the SoC did heat up, the GPU frequency was flat throughout the results. This is quite a bit different than all of the Core M processors, which had to throttle both the CPU and GPU as needed. It is very interesting especially in the UX305 results to see that the GPU is throttled on high CPU workloads to give more headroom for the CPU, which you can see on the third heat spike in its graph. This would be the physics test, which relies heavily on the CPU. The Dell Venue 11 and Yoga 3 Pro had very different temperature curves, and the Yoga 3 Pro had to throttle the GPU quite a bit to stay at its target SoC temperature.
Looking at the average CPU frequencies reaffirms what we have seen in previous results. The ASUS, despite having the lowest turbo frequency, has the highest average for the Core M devices. But it is the GPU frequencies which are the most important in this test.
All of the Core M devices had to throttle the GPU to some extent, but the ASUS did the least. The Yoga 3 Pro and Dell Venue 11 Pro were basically tied in average GPU frequency for the duration of this test. GPU workloads can pull a lot of power into the SoC, which can raise temperatures as we will see in the next graph.
Looking at the SoC temperatures explains the results. The Yoga 3 Pro has an average of 65.2°C, which is the target temperature for the Yoga. This means it was not able to leverage the breaks in workloads to ramp up its higher turbo frequencies when needed. The Dell Venue 11 is at almost 90°C for the benchmark, and that is also its limit. The ASUS, with its better cooling, manages to basically mirror the Core i5 for SoC temperature.
The excellent cooling of the ASUS form factor shines in the GPU tests. For the overall score, it comes very close to the Core i5. Both of the 5Y71 devices struggle under sustained GPU workloads, as the scores confirm.
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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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