Both Demos were crazy good but that Crest 2010 demo was pretty sick.... I don't remember a memory expansion ever coming out for the C64. Heck I bought the C64 a couple of months after it came out when I was a kid. Spent all my newspaper money.
There were three RAM expanders out for the C64/128. The 1764 was 256k and the 1750 was 512k. The 1750 was only intended for use with the 128 but clipping out a capacitor allowed it to be used with the C64 also using a beefed-up power supply unit. The 1764 came with the power supply upgrade already. The 1700 was only 128k and I don't think I'd ever seen one of them that hadn't been upgraded to use bigger RAM chips.
