I ran my system with 36K for the longest time. The original 4k, plus 2 banks of 16K. If I recall correctly, the after market DRAMs were at least $20 each. Thus, the 2 banks cost over $300, which was a lot of money to a college student bringing home $60 a week from a part time job. This was in first half of 1978. Regards, Mike Willegal