Sinclair Research unveiled a new computer at a press conference in England in mid-March. The ZX81 comes with the same 8K ROM that will be available for ZX80s and 1K RAM and sells for 30% less than the original ZX80. Sinclair does not plan any export sales so far, and has not submitted the ZX81 for FCC approval in the US.
The new machine is smaller than the ZX80, measuring 6 , 3×6 , 8 x l.5 inches . It operates in 2 software-selectable modes, fast and slow. Fast is 4 times the speed of slow, and according to Sinclair, compares favorably with other personal computers. The slow mode permits continuous display even while calculating. Sinclair replaced 17 TTL chips with a custom-built chip and included only 1 RAM chip, so the ZX81 has only 4 chips altogether.
The ZX81 will also be available in the UK in kit form for about $100 US.