Focusrite Scarlett 8i6 issues with Cubase

I have just bought a Focusrite Scarlett 8i6 USB 2.0 audio interface to replace an aeging M-audio Delta 44 (whose i/o box is getting past it).
Initially (even with their latest drivers) I had tremendous USB disconnection issues until I moved to a different USB port (away from the Steinberg dongle key). With that seemingly solved I opened Cubase 6 only to find very bad latency issues. I switched back to the M-audio and also a Guitar Rig Kontrol 2 USB interface and both had almost innaudible latency when monitring an input through Cubase. I switch back to the 8i6, but I hear something like 250-500mS of delay in the monitored signal despite the 8i6 showing about the same latency as the M-audio in the devices setup screen.
I ran up guitar rig with the 8i6 and got very low latency in the audio.
I know I can use direct monitoring with the 8i6, but it is nice to run guitar through some FX whilst recording, which I never had an issue with on the older hardware. I just can’t work out why it only seems to be an issue when running Cubase.
Just wondered if anyone lese had seen this or had any pointers

Kit:
PC i5 core (can’t remember the speed off the top of my head
Windows 7 Home 32-bit

PC is reasonably well optimised for audio, well no real issues with the other interfaces anyway.

Simon