The matter seems to have an explanation.
I mentioned the problem to an IT nerd acquaintance who said he’d check the card for me. He reckons that I’ve bought a clone. The lettering is wrong on the card, and the connections are ‘crude’. He reckoned that’s probably why the auto driver update wasn’t working. It seems that one of the outputs was faulty as well, although I didn't use it for the VDU screen I was viewing PowerDirector on.
I’ll stick with the on-board Radeon graphics. It runs both screens at 1920 and the preview at HD without any hanging. My pet nerd reckons that at 32gb RAM, it should cope without problems. Any advice from the knowledgeable gratefully received though.
I bought the card from a well-known online multi-national retailer at just a little below the going rate; no more than 10% I’m sure. It wasn’t cheap though. I’m irritated that I have been conned, although only to an extent I suppose. I’ve had good use of it for some years. I’m still irritated though.
It’s the old adage: buy something that costs 10% more than the going rate, and you’ve lost 9.09% of the price you paid. Pay 90% and you might lose 100%.
Thanks for all your help. My problem has been solved, and that’s a big positive. I've had a look at advice on these forums for a suitable graphics card for PD and there is no consensus, so if it works, stick with it I suppose.
Thanks again.
I love aphorisms: they give all the appearance of intelligence without any of that difficult thinking.