Amstrad acquired Sinclair at some point fairly late in the game, and they produced the 1000 series of PC’s including the lower end PC-1512 and the higher end 1640 as their first branded entrance to the PC Market before the 2000 series of PC followed on a year or so later.
The Principal difference between the two models was the RAM, with the 1512 having only 512k, and the 1640 having .. wait for it… 640k.
Both PC’s had choices of Single 5.25″ Drive, Dual 5.25″ Drive, or Single 5.25″ Drive plus Hard Drive models.
Graphics on the 1640 were provided with a choice of Hercules Mono, CGA, or EGA (640×350 in 16 Colours).
I remember a friend who had invested Thousands in a PC1640 with Hard Disk and EGA Colour display went on to have horrendous problems with his Hard Disk as it kept developing “Seek Errors” and a very odd Whistle-Clunk every few months and so he’d have to keep reformatting the hard drive.
Both models came provided with the GEM/3 Desktop environment and a few apps.