[ZTE Axon 7 Guides, News, & Discussion] Infy_AsiX:
Hello Axon 7 users, I just picked up one a couple of days ago. After finally figuring out the bootloader, bootstack and general stock experience I tested a little bit of gaming. I found that a basic game like Clash Royale heats the battery up to around 42°C already with low brightness and slow charging. A more intensive game like the new Knives Out runs only slightly hotter but it becomes apparent that CPU gets throttled soon after loading to 1036MHz across all cores causing lag.

It's disappointing so I tried to find how to modify the throttling. Using ZTE's Power Manager setting on performance or balanced doesn't seem to have a noticeable difference.I tried the only stock custom kernel AX7 but it's outdated on B32 and I find it randomly reboots regularly. The stock kernel itself allows some configuration, but the thermal settings in Kernel Adiutor don't reflect any charge.

A quick Google search brings up how LG V20 Snapdragon 820 users edit /system/etc/thermal-engine.conf to tweak the throttling levels. Their config is quite different but they mod big to 1824Mhz and let little scale itself.

I couldn't get thermal-engine.conf to use the thermal-engine-8996-perf.conf values by copying the values to it as it suggests inside. I tried renaming it with the -zte.conf ending as it suggests as well but that didn't work. After just renaming both the normal and perf conf files with a .bak ending, I've found better throttling performance. Big now throttles to 1632Mhz and little to 1324Mhz. As far as I can understand the files don't have charging rates inside, just GPU and CPU throttling.

However as expected the device heats up a few degrees more now. This now puts my battery up to 47°C in Knives Out under the same conditions. Charging is stopped at 45°C by the system so as previously mentioned it's unmodified.

I just wanted to check since I couldn't find it mentioned. Is everyone ok with gaming performance limited to 1036Mhz with the normal throttle? Also are my temperatures normal? I guess CPU doesn't seem that high reaching around 65°C, it's just that the battery has less than 20°C difference in intensive performance. I suppose it's a quirk of the heat pipe to battery as heatsink design. I just expected more from a metal unibody chassis and at least normal CPU gaming performance. I thought my Sony Z3 Compact design was bad for battery thermals, with the battery stacked behind the CPU board, sandwiched in insulating glass. But I didn't expect to see a phone to route a heatpipe directly to it's battery.

Anyway it is what it is. Follow this information if you want some better gaming performance at the cost of your battery cycle life. In my case I bought the Axon7 just as a separate media consumption device rather than a phone so I can live with the tradeoff. If battery gets bad enough before 2 years I'll consider using warranty at the loss of receiving their refurbished replacement. Manufacturer warranty's in fact cover batteries for 80% depletion.

I recommend the app DevCheck Pro for being able to monitor CPU, GPU, temperatures and other things overlayed. I think some others may do similar but they may not be updated for Big Little and are more instrusively overlayed.