why ESS is light at using system resources?

I can see in my task manager that ESS is using around 30 to 34 mb of RAM and while scanning it uses around 40 to 50 mb and 15% to 45% of cpu.
when i was testing KIS 7 on same computer it was using 10 to 30 mb RAM normally and 40 to 50 mb RAM and 40% to 65% usage of cpu while scanning.
Now my question is, it was clear to me that system was bit slow when kaspersky was installed and i felt system drag. BUT there is no question of system drag or slowness while using ESS.
So can anyone tell me why is it so?

 

While I expect ESS to end up being lighter than KIS, when it's done, one thing to keep in mind is the ESS is not feature complete yet, so it's not really a fair comparison... "yet". Some of those missing features may or may not negatively impact ESS's performance. Time will tell.