Occasional bird snapper
You do not have to have any noise reduction applied Dave - just switch of any Noise reduction by zeroing the sliders. I do not convert to a tiff before transferring to Photoshop, its is done automatically when selecting selecting 'send to photoshop'. The time taken to 'send to photoshop' is just a few second on my ageing (10 year old) PC.I rarely use DPP to edit as I find that it applies noise reduction automatically which even when reduced to it's lowest sometimes over does it. If I drag a file from DPP in to Photoshop I get the full original file untouched. Is this why you convert to a TIFF file Roy, to preserve any changes you have made in DPP?
I run the DLO in DPP and also turn off noise reduction which is why I use 'send to photoshop' from within the edit image window instead of just dragging.