We have a few PE T330's. One of them is having serious issues with data transfers where it will time out when copying large files. Normally anything over a GB will produce the error. This seems to be mainly on uploading files rather then downloading from the server. The set up is similar to the other servers we have. The data store is 5x6TB drives hardware RAID 5 on a PERC H330 adapter. We have tried updating the NIC drivers with the latest driver from Broadcom and updating the network firmware.

What we are seeing is the upload will start well at good speeds. Then after a while, and the amount of time or data when it occurs is not consistent, the transfer will slow and stop. After a while we will either get a Semaphore time out or get an error that the location is no longer available. The server is still accessible through the mapped drives when these errors come up. 

Do you have any idea why this might happen or what we might try to fix the issue?