CPU high usage on one core

[ImLovely]

I started playing an mmorpg called Trickster Online. I noticed that sometimes, randomly, it would spike in usage on one of the cores of my CPU and stay that way. If I changed the affinity the usage would just skip over to the next core. I've noticed some other applications tend to stick to one core although a different one, like core #3 instead of #2. What is the cause of this?

Here's a screenshot:
http://img140.imageshack.us/img140/8787/usageproblem.jpg

 

[amuffin]

Is there a problem?

 

[ImLovely]

Well I don't know if this is normal or not. Shouldn't the usage be spread out among all 4 cores instead of stuck mainly on one?

 

[amuffin]

Not if the program is single threaded.

 

[ImLovely]

Alright, maybe it is. I couldn't find any information on the application about that though so I decided to ask here just to be sure. Thanks anyways!