2.2Ghz is not enough to run CS:GO.
CS:GO only uses 1 core on linux (some might be offloaded to a second core but not much) so you need a higher clock speed, something 3Ghz or higher.
Also make sure that the server is not using powersave otherwise your clock speed will go down. You can disable it with this command
Code:
echo performance | sudo tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor
performance