The auction house originally estimated the item would sell for $120,000 to $180,000, CNET.com reported Friday.
The motherboard is operational, marked "Apple Computer 1" and dated 1976.
"It is thought that fewer than 50 Apple 1 Computers survive, with only [six] known to be in working condition," Sotheby's said in the auction catalog notes.
The original Apple 1 computers retailed for $666.66 in 1979 and purchasers had to procure their own monitor, keyboard, case and power supply.
The motherboard has a MOS Technologies 6502 microprocessor and 8 kilobytes of RAM.
The auctioned unit is one of only about 200 Apple 1 computers produced.