Thanks to all for the feedback.
Goes like lightning sounds fun to me. Planning to port other bits of hardware to the new mobo if I do it - already got an SSD, which made a huge difference. Likewise, 12GB of RAM - can't recall the speed rating off-hand but might be something to think about upgrading also.
@mix
In truth, there's nothing in the current set up that is really causing me problems. Occasionally things are slow enough that I wait, some of the graphics are PSDs running to several hundred MB with many layers - final image may get flattened and JPGed but the source images are not mine and they have to stay in their original glory in the master file so that different layers can be used or hidden in the final image. For vector stuff I tend to use CorelDRAW, I prefer it to other options and know it well but sometimes I end up waiting as it redraws some very complex graphics, typically that have been imported from PDFs, but from experience it is rather buggy and I'm sure it's not the most efficiently coded program. Final challenging task, the long documents - for text-based docs I prefer to use FrameMaker but for shorter ones or where there are plenty of graphics I will use InDesign. Some of the FM books run to between 2 and 3 thousand pages - fortunately I only publish, others do the writing!
The urge to get a new toy at the moment is buoyed by a bit of money that got earmarked for IT in a business plan and hasn't been used rather than any real need - but what's wrong with boys' toys?