fiber network speed slow

We have bought a few HP HPE Aruba 6100 class 4 POE with 4 SFP+ ports each. We have wired for redundancy and have been running tests physical to physical and virtual to virtual and are getting speeds of about 3gbps as opposed to the 10 we hoped to get. We are currently using vmware so would like to get a vmware network engineer to troubleshoot with. We cannot seem to understand where the bottleneck is. We have used 10gtec and HP transceivers and these are not making a big difference to the figures we are seeing.