SanDisk Ultra micro SD 512Gb write speed

[Alpaca77]

I bought a used SanDisk Ultra 512Gb micro SD on eBay. It writes at 7-8 Mb/s which I think is absolute rubbish. It reads at about 60 Mb/s.

I have other makes of card which give me write speeds of around 40-50 Mb/s. None are top of the range Extreme or Pro type cards.

Is my Ultra writing normally or is it a dud card?