It probably says "21.5", as the 20" iMac was discontinued (except the education store I suppose) in late 2009.
If you have a 2011 iMac, it will support up to 32 GB RAM using four 8 GB 204-pin DDR3 SO-DIMM RAM modules.
it probably says "21.5", as the 20" imac was discontinued (except the education store i suppose) in late 2009.
If you have a 2011 imac, it will support up to 32 gb ram using four 8 gb 204-pin ddr3 so-dimm ram modules.