bad lag spikes with r9 270

[GetScared25]

i bought a new graphics card a few days ago and when i installed it games now get really bad lag spikes for 5 to 10 seconds and sometimes freezing but wont crash. i upgraded from a hd 6670 1gb ddr3 to a gigabyte r9 270 oc. everything is running on stock settings as i just want to do some mild gaming nothing super crazy. i have updated drivers, scanned for viruses, malware etc. the 6670 could run far cry 3 on medium settings perfectly but i cant even play it on the same settings now because the lag spikes are always happening. please help i would appreciate it

my pc specs:
mobo: asus m5a97 r2.0
cpu: amd fx 6300 stock settings
gpu: gigabyte r9 270 oc
ram: 4gb kingston 1866 ram
psu: rosewill stallion 500w
hdd: western digitial 500gb

 

[ZeusGamer]

When you said you've updated your drivers, I'm not sure if you just updated them without uninstalling them first or what . You should always do a full clean install of the drivers. Download the latest BETA drivers from AMDhttp://www2.ati.com/drivers/beta/amd-catalyst-15.4beta-64bit-win8.1-apr9.exe[b. Then use Display Driver Uninstaller and uninstall your drivers. When it prompts you to go to safe mode, make sure that you do. Then when you get back into Windows, install the drivers that you downloaded prior to downloading DDU.

UPDATE
Either that, or the CPU is bottlenecking your GPU. You can try overclocking it to maybe 4.5 GHz to alleviate the bottlenecking for a little bit. Good luck!