[Nexus 6P General] XCnathan32:
So me typing this reply ended up in me going about a long rant about my theories about Qualcomm. Tl;Dr to your question: Stock 6P uses 8 cores, fixed 6P uses 4, Qualcomm 810 using 8 cores probably overheats so much, that it thermal throttles heavily, resulting in performance only slightly higher than the same processor, with 4 cores, that thermal throttle much less.

Trigger warning for anyone about to read this: I harshly bash on Qualcomm in this semi-angry rant, if you are a diehard Qualcomm fan, you should probably not read this.

On a stock Nexus 6P, 8 cores are enabled in ARMs big.LITTLE configuration. big.LITTLE is where there is a cluster of power efficient, slower cores to handle smaller tasks (in the 6P's case, 4 Cortex A53s running at 1.55GHz), and a cluster of more power hungry, high performance cores (for the 6P, 4 Cortex A57s running at 2GHz)

On a bootlooping 6P, a hardware malfunction related to the big cluster causes this bootloop, so this fix remedies the problem by disabling the high performance big cores.

The stock 6P is supposed to use the Cortex A57 cores and some of the Cortex A53 cores for foreground tasks. So you would think that a working phone should have double the performance of a phone with this fix, right? After all, it's using 4 more cores, and those cores are clocked almost 25% higher. The reason that (I think) performance is not noticeably affected, is because Qualcomm's Snapdragon 808/810 SoCs, are a horrible, rushed project, that could be designed better by a group of monkeys.

Even with 4 cores disabled, my phone can still thermal throttle (for those who don't know, thermal throttling is when CPU/GPU performance is intentionally limited by software to keep temperatures in check) when playing games, or even watching YouTube. The big cores run way hotter, and they thermal throttle insanely easily, see this graph here. In 30 seconds, the big cores are already to 1.8GHz (From 2GHz), in 60 seconds, the big cores are down to 1.4GHz, and in 3 minutes, 3 freaking minutes, the big cores are thermal throttled down to

850MHz

, which is 235% slower than the advertised 2000MHz, and 182% slower than the little cores 1.55GHz.

So my guess is that the big cores thermal throttle so easily, and the high heat output of the big cores results on the little cores overheating, which results in the little cores being thermal throttled along with the big cores. So 4 cores that typically do not thermal throttle, are better than 8 which do. Either that, or when the big cores overheat, the device turns off the big cores and only uses the little cores, which is essentially this fix.

For those of you that think my description of the 808/810 was slightly (extremely) harsh, you're right. However, here's why I was so hard on them: I feel like Qualcomm rushed development of the 808 and 810 to get it to flagship devices. The 808 and 810 were also the first (and last) of it's processors to use the TSMC 20nm manufacturing process. So my guess would be that Qualcomm designed the processor based on that manufacturing process, and then after finding out about the poor thermals of their new chips, it was too late to redesign their chip, because they had to give it to manufacturers. After all, a "Flagship device" can't use a last gen processor. So the overheating chips were given to manufacturers just so their phone could look better on a spec sheet.

Also, Qualcomm VP McDonough said "The rumours are rubbish, there was not an overheating problem with the Snapdragon 810 in commercial devices"(source). However his response to heat issues and benchmarking problems in the early Flex 2 and One M9 was because they weren't final commercial versions of the devices. "Everything you're saying is fair. But we all build pre-released products to find bugs and do performance optimisation. So when pre-released hardware doesn't act like commercial hardware, it’s just part of the development process." In that context, performance optimisation most likely means "allow the devices to run hotter than they should before they throttle" (source) which results in problems later down the line (like maybe half of the cores failing, causing a record number of bootloops in devices?)

The whole reason I typed this rant, was to express my frustration at how Qualcomm (most likely) caused tens of thousands of people to have devices that performed worse than they should have performed on paper, and even result in broken devices. And I haven't seen many people blame Qualcomm for the bootlooping problem, and everyone blames Hauwei/LG/Google, while Qualcomm twiddles their thumbs and keeps ranking in money for their domination in the mobile SoC market. Now obviously, I'm not 100% sure that Qualcomm is to blame for the bootlooping problems, and no one will probably ever know who caused the problem. So this is just a theory that I have. But it is awfully suspicious how the same chip has had problems in multiple devices, even when different companies manufactured the devices.

Even if Qualcomm isn't to blame for the bootlooping problems, it is hard to deny that their chips have serious overheating issues. Samsung themselves basically admitted that the 810 had problems, as every single one of their Galaxy S devices (at least US models) have used a snapdragon processor, except for the galaxy S6, where Samsung opted to use their own Exynos processor instead of the 810, even on the US model.

Please feel free to reply and discuss/argue my points, as I would really like to hear what you guys think about my theory.