Hey Hemansu!! Iknow its prolly 7 years too late lol BUT!! The reason the spikes are happening is most likely due to the setting in
Studio Setup > VST Audio System > “DISK PRELOAD” is set to 2 seconds. I switched the setting to 6 seconds and the spikes stopped! 
In the HELP/manual it says:
“Disk preload is the amount of audio data that is loaded into RAM prior to starting playback. The purpose of this is to ensure smooth playback”
Hope this finds you well!