I tried testing this out. Here are the results for those interested:
I ran 3 java applet within single account meaning 3 accounts within same client. I couldn't run more then 3 tabs within single client without having the entire client lag as shit. Using 3 tabs within single client reduced my CPU usage by averagely 5% each tab.
So as long as you use multiple accounts on single IP and don't use proxy, I advise using 3 tabs/java applets per 1 client to reduce your CPU usage.
Have fun botting, guys