it has built in protection , but better to have surge protector . i have many brownouts and spikes , blown many a tv and other componentse , now have ups on all computers and tv;s , have not had a problem since
Always recommend a surge protector.
.. They do nothing for Brown outs, Low voltage
.. No protection from Loss of power
.. No protection for "low energy" spikes
So what does the Surge protector really do.
.. Protects against High energy spikes. For example a Near By (Not a direct hit) by lighting can create a Large energy spike.
.. When The AC drops to zero momentarily then comes right back on, some appliancies can generate a large spike which may trigger The protection circuit - often it is not high enough.
NOTE: The protection circuit is normally a self destruct circuit which means if you trigger it you will need to replace the surge protector.
Above reasons are why you should have a UPS + Surge protector (Most UPS have a built in surge protector).
Bottom Line when you can afford the UPS - Get it. It is cheaper than replacing the computer.
My Aunt had a lighting strike. She had a surge protector - NO help she still lost the computer. Reason the Spike also came in on the phone line and she had a mode connected.
A common misconception, that many people make, is that surge protectors last forever.
The MOVs that are used in a surge protector are sacrificial devices and will lose a little bit of their ability to suppress voltage spikes with each voltage spike that it has suppressed. Eventually the surge protector becomes just a power bar with no surge suppression ability remaining. The good surge protectors (i.e. expensive ones) have a circuit that detects when the MOVs are unable to provide adequate protection any more and will display an indicator light and/or disable the use of the surge protector.
Surge protectors that only use MOVs are suppose to be replaced every year.
If you want something that protects against brownouts(most common thing to cause damage) and over-voltages look into a AVR it also has surge protection built in it is also fairly cheap like this APC unit.