How do I limit backup's resource utilization

[kristow]

We're a 24hr shop, and when the backup job starts it seems to take all of the server's resources, preventing users from connecting to the server. How can I limit the resources that backup uses?

Netware 6.5sp8
Tivoli client 5.5.2
Dual core 3.0ghz server, 4gb ram.
I've changed the Cache Memory Threshold to 1.

Full TSA.CFG
Read Buffer Size:
65536
Read Threads Per Job:
4
Read Thread Allocation:
100
Read Ahead Throttle:
2
Cache Memory Threshold:
1
Disable Cluster:
yes
Show Cluster Volumes On Node:
no
Enable GroupWise:
0
Enable Caching:
yes
Disable Demigration:
no