Galaxy with Clutser too slow

Hi guys,
i hope somebody can help me, i am trying to connect Galaxy with our Cluster. We use the Son of Grid Engine. I can submit jobs but it takes to long to finish them
When i am submit jobs without the connecting to the cluster, the jobs are finish by far faster.
Maybe this is important to: when a normal user submit a job to the cluster, the job takes all of the cpu time he can get but when we submit a job through galaxy the job takes only about 25% of cpu time

thanks in adavance!