Xonar DG Crackling More Than Onboard? K271 Suggestions?

Hey guys so I just got the Xonar DG and I have set all my settings right I believe. Check the pictures below:

And here are my FL Studio settings:

So what could be going wrong? Is this something I should expect from a $30 soundcard? I mean I thought a soundcard would at least be better than Onboard, but why is this soundcard crackling way more than my onboard? Im pretty sure I installed the card correctly. I put the card in, turned on computer, canceled the automatic driver installation and used the disk to install the drivers. I even went on the ASUS website and updated my Xonar DG firmware to current version.

So can you guys help me out? I would deeply appreciate it cause this is really bumming me out :[ If it helps, here are my PC specs:

ASUS M3A32-MVP Deluxe Motherboard

AMD Athlon 64X2 Dual Core Processor 5200+ 2.97 Ghz

4.00 GB RAM

1 GB ATI Radeon HD 5770

ASUS Xonar DG Sound Card

500 GB HDD 7200 RPM

Windows 7 64-bit

Thanks guys,

AuTra

I am also using AKG K271 MK2 and Sennheiser 280 HD Pro headphones. I still think the 280s have clearer mids than my AKGs even after I got this soundcard :/ The AKG makes vocals hurt my ears and when people sing their 's' is really loud and annoying. Every song needs a de-esser pretty much with the K271s.

I'm thinking about return the K271s for something else. What do you guys recommend I should switch it out with? My budget is below $200

Hmm it may be CPU related. On FL Studio it does show that I'm using 99-100% of my CPU. I thought a soundcard makes up for CPU usage or am I wrong?