Projects loading very slowly in 17b2

17b2 - To load a project previously created in Resolve 16.3 - loads to 90% then sits there for nearly 40/50 secs before it finally loads. It I save the project it takes around 35/40secs to do so. If I export the project it takes around 40-50secs to do so. Pretty sure it never took this long before, certainly a simple save was pretty much straight away. If I right click a time line in Media to change the TC for example it takes around 1 to 2 mins and sometimes more before the turning blue circle goes and I can make a change.

Project is 1.6TB of mostly BRAW 5:1 4.6k and some 6k with a very small amount of drone footage mp4 all at 25fps on one 2TB SSD.
Windows 20H2
i7 10 core - RAM 64GB - Graphics 2 x Quadro K6000 12GB's (24GB) which easily play Braw no problem at all with no need for proxies, not even with quite a few colour nodes and effects added.

Anyone any clues on what the problem is and or how to fix please?
Thanks
Richard

I don't have any big projects in BRAW. (Got my Pocket right at the start of Shutdown.) All my larger projects are in cDNG or ProRes, but I'm not seeing this kind of thing with much lesser hardware.

I'm only seeing it on one project really the others while slowish aren't massively different so I wonder if this has to do with importing a 16 project into 17?

Well, all of my larger projects were created in 16, so...there's that.