Hi Jeron,
Did you check SU56 - the number of authorization objects - is that a big number ?
Activate trace on WF user for some time and check what all it does.
In SM50, do you see any related information on any process ?
How about ST03N ?
Also, check workflow related issue, refer :
Note 1098805 - Troubleshooting Tips & Tricks for workflow issues
Note 888279 - Regulating/distributing the workflow load
Divyanshu