Nvidia gpu on esxi

Im unable to power on my windows WM with PCI passthrough enabled for my nvidia GTX 750Ti gpu

error as below

Failed to register the device pciPassthru0 for 6:0.0 due to unavailable hardware or software support.

and in the logs is:

2019-03-21T15:25:52.321Z cpu22:2100708)VSCSI: 273: handle 8199(vscsi0:0):Input values: res=0 limit=-2 bw=-1 Shares=1000

2019-03-21T15:25:52.330Z cpu22:2100708)PCIPassthru: 2820: Can't use virtual IOMMU with devices with dependencies sbdf=0000:06:00.0

2019-03-21T15:25:52.332Z cpu22:2100708)VSCSI: 6602: handle 8199(vscsi0:0):Destroying Device for world 2100709 (pendCom 0)

looks like an issue with IOMMU is this somthing that can be fix'ed this is a bit beyond my knowledge .

any help would be greatly appreciated, also this is on a Dell T410 with latest bios

thanks