HDD Defragmentation..Good or?

[DarkPower202]

Just wondering if its safe to defrag files, power cuts here sometimes and am afraid of losing files while defragging..

I have a 500GB Seagate HDD and a 250GB Maxtor HDD,
%13 fragmented files on system disk, %4 on the other 2s.

I've defragged those 2 %4 local disk already, it takes an hour to do so.
Idk much about defragging, does it improve the hdd performance? (minimize loadspeed etc)

Thanks in advance!

EDIT:
I also have a problem with it, sometimes if i play heavy games for too long the HDD makes some sorta noise like it just shutsdown and then the game freezes (PC lights, no response), 20-30 seconds later it makes the same noise again and the game goes back to normal (and it happens all over again)

[Matt]

Defragmentation is good
Just NEVER do it on a SSD

Also yes it makes loading faster

[Exterminator]

Unless you're running Windows XP you don't need to defragment your disk.

Windows 7 and above automatically defrag the disk as necessary and there usually isn't any performance drop at all (Unless your HDD is failing). The frag % is harmless.