[Xperia Z2 General] Haldi4803:
Made some tests with User Control Hotplug and battery drain!

GovernorTest NR: 25 4 cores active

Modified Stock Rom 402 + Doomkernel v09

User Control Hotplug, ondemand governor, Trepn Profiler running (BatteryPower only!)

10 Minute Test, "normal" preset

Minimum screen brightness

Core 0	Core 1	Core 2	Core 3
300000	0.00 %	32.42 %	30.50 %	0.00 %
422400	0.00 %	1.90 %	2.10 %	0.00 %
652800	0.00 %	2.75 %	3.62 %	0.00 %
729600	0.00 %	0.56 %	0.71 %	0.00 %
883200	0.00 %	0.83 %	0.82 %	0.00 %
960000	0.00 %	45.95 %	47.15 %	0.00 %
1036800	0.00 %	0.32 %	0.38 %	0.00 %
1190400	90.08 %	5.84 %	6.54 %	91.90 %
1267200	0.24 %	0.20 %	0.18 %	0.16 %
1497600	0.33 %	0.48 %	0.41 %	0.27 %
1574400	5.21 %	5.09 %	4.53 %	4.22 %
1728000	0.12 %	0.10 %	0.12 %	0.05 %
1958400	0.18 %	0.15 %	0.05 %	0.12 %
2265600	3.85 %	3.41 %	2.89 %	3.26 %
2457600	0.00 %	0.00 %	0.00 %	0.00 %
Total Online	100.00%	100.01%	100.00%	99.99%
Total Offline	0.00 %	-0.01 %	0.00 %	0.01 %

Batterydrain: Average: 439.88mA Total: 75.90mAh in 621Seconds

GovernorTest NR: 28 3 cores active

Modified Stock Rom 402 + Doomkernel v09

User Control Hotplug, ondemand governor, Trepn Profiler running (BatteryPower only!)

10 Minute Test, "normal" preset

Minimum screen brightness

Core 0	Core 1	Core 2	Core 3
300000	0.00 %	25.29 %	24.76 %	0.00 %
422400	0.00 %	2.56 %	2.33 %	0.00 %
652800	0.00 %	3.45 %	3.67 %	0.00 %
729600	0.00 %	0.75 %	1.03 %	0.00 %
883200	0.00 %	0.85 %	1.02 %	0.00 %
960000	0.00 %	46.19 %	46.02 %	0.00 %
1036800	0.00 %	0.70 %	0.67 %	0.00 %
1190400	82.61 %	5.66 %	5.80 %	0.00 %
1267200	0.35 %	0.31 %	0.47 %	0.00 %
1497600	0.93 %	0.94 %	0.69 %	0.00 %
1574400	7.66 %	6.70 %	6.75 %	0.00 %
1728000	0.28 %	0.22 %	0.27 %	0.00 %
1958400	0.35 %	0.21 %	0.38 %	0.00 %
2265600	7.82 %	6.20 %	6.20 %	0.00 %
2457600	0.00 %	0.00 %	0.00 %	0.00 %
Total Online	100.00%	100.04%	100.06%	0.00 %
Total Offline	0.00 %	-0.04 %	-0.06 %	100.00%

Batterydrain: Average: 458.68mA Total: 77.85mAh in 611Seconds

GovernorTest NR: 27 2 cores active

Modified Stock Rom 402 + Doomkernel v09

User Control Hotplug, ondemand governor, Trepn Profiler running (BatteryPower only!)

10 Minute Test, "normal" preset

Minimum screen brightness

Core 0	Core 1	Core 2	Core 3
300000	0.00 %	22.39 %	0.00 %	0.00 %
422400	0.00 %	3.26 %	0.00 %	0.00 %
652800	0.00 %	5.62 %	0.00 %	0.00 %
729600	0.00 %	1.45 %	0.00 %	0.00 %
883200	0.00 %	1.52 %	0.00 %	0.00 %
960000	0.00 %	33.17 %	0.00 %	0.00 %
1036800	0.00 %	0.92 %	0.00 %	0.00 %
1190400	69.18 %	5.07 %	0.00 %	0.00 %
1267200	0.70 %	0.72 %	0.00 %	0.00 %
1497600	1.71 %	1.82 %	0.00 %	0.00 %
1574400	9.15 %	8.62 %	0.00 %	0.00 %
1728000	0.76 %	0.62 %	0.00 %	0.00 %
1958400	0.74 %	0.72 %	0.00 %	0.00 %
2265600	17.76 %	14.15 %	0.00 %	0.00 %
2457600	0.00 %	0.00 %	0.00 %	0.00 %
Total Online	100.00%	100.04%	0.00 %	0.00 %
Total Offline	0.00 %	-0.04 %	100.00%	100.00%

Batterydrain: Average: 456.99mA Total: 80.13mAh in 631Seconds

Even with User Control Hotplug it seems NOT possible to have just 1 core active!

P.S if you wonder where NR 26 is? here core Hotplug did not stick and 4 cores were active! i think this happens because the phone went into deep sleep after i choose the setting. i did not let this happen with the other tests.

Conclusion:

Deactivating Cores will NOT help you safe battery on a moderate daily usage!

If you're using photoshop apps or other really power hungry apps that might look different, but for normal web browsing, facebook and whats app that does not help!