On switches you can't have a collision, they are layer 2 devices with queues. Collision domains were a problem back in the day of hubs because 2 devices could send at the same time. Hubs operated on layer 1 and you would split collision domains with a device called a bridge, it would take packets and store and forward them between the collision domains. A switch is just a multiport bridge, each connection on a switch is its own collision domain since the device will store and forward for each segment.
Odds are your issue are a cabling issue, or a bad NIC on the server, or a bad switch/port on switch somewhere.
It also could be a software issue on the server causing the issues.