Same problem on 2 different pc's

I have been having a problem on my current rig,and i noticed that it is like the problem i was having on my last rig,yet the only part they have in common is that hard drive which i took from the old rig,i did use it as an OS drive for a little bit,then i got an SSD,and now use the drive as storage.

The problems is that in some game i get random fps drops,and in others i get just low fps,but the games i had the problems with were different on my current rig than on my old rig,on my current rig,i get fps drops in batman:AC & Diablo 3(only 2 game i know of so far)and u get low fps in batman:AC & arma 2,on my old rig i got fps drops in cod:mw2 & mafia 2+ i think a few games that i don't remember,and i got low fps in GTA:4.

 

My current rig:

[email protected] stock

Sabertooth990FX

8GB of ddr3 1600mhz

Reference 7970 3GB

Cougar 1000w psu(i know it is overkill but i "WAS" planing on adding more video cards,and hard drives and ram lol)

OCZ agility 3 60gb

Seagate 1.5TB SATA 2 hard drive(the drive that was on my old rig)

old sata WD 250GB

My old rig:[email protected]

XFX 680i LT

4GB of ddr2 1066mhz

GTX460 SE 1GB

Ultra X-Pro 600w

Seagate 1.5TB SATA 2 hard drive

 

I have no clue what is causing this weird problem.

Is anything perhaps overheating?

Do you use a custom windows ui? Th setting windows to widows basic. See if that fixes it

 

No over heating on either rig.

On the old rig i don't remember what i had it set on,but i my current rig i have it set to basic.