Its hard to make this work on a server. This feature works better to combine links between core switches.
The worst case that you cannot fix is if the traffic is going back and forth between 2 machine. 802.3ad does not have the ability to load balance traffic it will pick a path based on a combination of mac addresses and ip addresses. Since 2 machines will always have the same ip and mac addresses the traffic will always pick only a single path. It sometime even pick a different path for inbound and outbound but it will always use a single path.
It depends on how your network is structured and how you have this feature configured. You have some option to change which mac and ip it uses. There are some that by default only use only mac addresses which in a routed network means all traffic uses the gateway mac and the machine mac so you only get a single path utilized even for traffic coming from multiple machines.