Dragon Dictate issues

I am a long time user of voice recognition software, both PC (Dragon Naturally Speaking) and Mac (Dragon Dictate). I am running the current version of DD - v5.0.5 after coming back to mac after several years having to use PCs for work.

I have an iMac late 2014 with max RAM. It is my workstation so there are always open several apps - Word, Acrobat, calendar, Mail, Firefox, Filemaker.

I have used an Xtag microphone and recently upgraded to a TableTalk USB 9 in 1 microphone (said to have been specifically designed for DNS). The microphone is connected direct to the iMac, not through a hub. I use TextEdit but know that it is essentially incompatible with DD and so it is turned off when using DD.

Despite all my attempts, DD remains capricious - it loses recognition accuracy, place on the page (dictating into Word or Mail). It seems better than it was in ver 4 although I think the more powerful iMac may be assisting. DNS worked fairly flawlessly on my PC.

Am I pushing the envelope too far trying to have a "workstation" and DD running? Do I need a more powerful Mac? DD is sufficiently important to me in my day to day work to sort this issue out, even if it means a further upgrade.

Lexfx