[Redmi Note 2 Original Android Development] MOVZX:
I never limited my phone's CPU Clock to anything lower than 2.2GHz (Prime version) because I it's the reason I bought that Prime, 2.2GHz. If I prefer lower Frequency, maybe I could just bought another cheaper phone with lower frequency than limiting what my phone could do with it's 2.2GHz.

Battery usage is depending on our own usage, tweaks just help somewhat little-effect maybe even placebo.

This is my favorite CPU Settings for my Prime, it could be very low in frequency, but also could perform to the highest performance (mostly when running Antutu to see 59K+ score it achieved):

#!/system/bin/sh

# Set CPU to Max 2.2GHz (Prime)
echo "1" > /sys/devices/system/cpu/cpu0/online;
echo "1" > /sys/devices/system/cpu/cpu1/online;
echo "1" > /sys/devices/system/cpu/cpu2/online;
echo "1" > /sys/devices/system/cpu/cpu3/online;
echo "1" > /sys/devices/system/cpu/cpu4/online;
echo "1" > /sys/devices/system/cpu/cpu5/online;
echo "1" > /sys/devices/system/cpu/cpu6/online;
echo "1" > /sys/devices/system/cpu/cpu7/online;
echo "2158000" > /sys/devices/system/cpu/cpu1/cpufreq/scaling_max_freq;
echo "2158000" > /sys/devices/system/cpu/cpu2/cpufreq/scaling_max_freq;
echo "2158000" > /sys/devices/system/cpu/cpu3/cpufreq/scaling_max_freq;
echo "2158000" > /sys/devices/system/cpu/cpu4/cpufreq/scaling_max_freq;
echo "2158000" > /sys/devices/system/cpu/cpu5/cpufreq/scaling_max_freq;
echo "2158000" > /sys/devices/system/cpu/cpu6/cpufreq/scaling_max_freq;
echo "2158000" > /sys/devices/system/cpu/cpu7/cpufreq/scaling_max_freq;
echo "403000" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq;
echo "403000" > /sys/devices/system/cpu/cpu1/cpufreq/scaling_min_freq;
echo "403000" > /sys/devices/system/cpu/cpu2/cpufreq/scaling_min_freq;
echo "403000" > /sys/devices/system/cpu/cpu3/cpufreq/scaling_min_freq;
echo "403000" > /sys/devices/system/cpu/cpu4/cpufreq/scaling_min_freq;
echo "403000" > /sys/devices/system/cpu/cpu5/cpufreq/scaling_min_freq;
echo "403000" > /sys/devices/system/cpu/cpu6/cpufreq/scaling_min_freq;
echo "403000" > /sys/devices/system/cpu/cpu7/cpufreq/scaling_min_freq;
echo "interactive" > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor;
echo "interactive" > /sys/devices/system/cpu/cpu1/cpufreq/scaling_governor;
echo "interactive" > /sys/devices/system/cpu/cpu2/cpufreq/scaling_governor;
echo "interactive" > /sys/devices/system/cpu/cpu3/cpufreq/scaling_governor;
echo "interactive" > /sys/devices/system/cpu/cpu4/cpufreq/scaling_governor;
echo "interactive" > /sys/devices/system/cpu/cpu5/cpufreq/scaling_governor;
echo "interactive" > /sys/devices/system/cpu/cpu6/cpufreq/scaling_governor;
echo "interactive" > /sys/devices/system/cpu/cpu7/cpufreq/scaling_governor;

# Tweak Interactive CPU Governor
#
# Target Loads
# Using 90% (0.9) Loads and a calculation like this: Frequency*0.9/Next_Frequency, i.e. 403000*0.9/806000 = 45% (rounded up)
echo "90 403000:45 806000:61 1183000:80 1326000:80 1482000:80 1664000:79 1885000:79 2158000:99" > /sys/devices/system/cpu/cpufreq/interactive/target_loads;
#
# Above High Speed Delay
echo "20000 806000:60000 1183000:20000" > /sys/devices/system/cpu/cpufreq/interactive/above_hispeed_delay;
#
# High Speed Frequency
echo "1183000" > /sys/devices/system/cpu/cpufreq/interactive/hispeed_freq;
#
# Go High Speed Loads
echo "90" > /sys/devices/system/cpu/cpufreq/interactive/go_hispeed_load;
#
# Timer Rate
echo "20000" > /sys/devices/system/cpu/cpufreq/interactive/timer_rate;
#
# Minimum Sample Time
echo "30000" > /sys/devices/system/cpu/cpufreq/interactive/min_sample_time;
#
# Timer Slack
echo "80000" > /sys/devices/system/cpu/cpufreq/interactive/timer_slack;
#
# Boost
echo "0" > /sys/devices/system/cpu/cpufreq/interactive/boost;
#
# Boost Pulse Duration
echo "80000" > /sys/devices/system/cpu/cpufreq/interactive/boostpulse_duration;
#
# I/O Is Busy
echo "0" > /sys/devices/system/cpu/cpufreq/interactive/io_is_busy;