wow, what a difference! Just installed 2 sticks of 8Gb 2666Mhz Crucial ram, and it now works as expected, only one slight hiccup, when on first start up, it gave a white screen with the message that the memory had been changed, after clicking continue everything loaded and works fine. Photoshop Elements is so much faster and easier to use, no time to go and make a cup of tea.  My only gripe was that Crucial said despatch via Royal Mail 48 Hr, which took 10 working days from BRNO, Czechoslovakia,  maybe the 48 hr thing only applies when parcel is in UK. But I have it now, it works, so I don`t care.  Thanks to everybody for input John
I know that Dells prefer Crucial, but they have no stock! I wish to upgrade my Inspiron Desktop 3881`s 8Gb of Micron 3200 DDR4 to 16Gb but no luck at Crucial, and they do not seem to know when any is expected.  (The Acer CEO thinks the situation will ease mid year, but Micron think end of year )  Is there an alternative make of Ram that will work problem-free in a Dell, or do we just have to wait and hope? There seems to be supplies of other brands, just Crucial 16Gb is like gold dust. John
Ram Alternatives