Ctrl-alt-delete and spot the process that uses your cpu every 30 seconds, then google that process.

Edit: Start/Run/ then type "msconfig" then disable that process

I hear the PowerPlay feature isn't working yet. Once new drivers fix that, core and memory clocks will be lower at idle (core at probably 300-400 mhz). That plus custom cooling and rivatuner/ati tools later to raise the fan speed, problem solved.

And reapplying thermal paste will help too:

From the xtremesystems forums:

"Some notes before the testing. The fan speed very low on the factory bios, I haven't been able to use any fan control to raise the speed so far. The temp is most likely fine even with an Idle of 79c but Being an XS'er I removed the factory thermal goop and replaced it with A.S. Ceramique. the idle temps are now 55c most of the time."

http://www.xtremesystems.org/forums/showthread.php?p=3059788

I use avast antivirus free and firewalls from windows and my router are enough for me.

[Where, I havn't seen any.musclesforcier

Here it beats the 280

There and there it beats the 260 in AC and Grid

And here Bioshock

You can save money:

Memory 30$

Hard disk 70$