PCs in the second quarter accounted for 49% of DRAM shipments, down from 50.2% in the first quarter, IHS iSuppli said.
The market share of DRAM sold for PCs hasn't dipped below 50% since the 1980s, when computers were new and sales were booming.
That they have lost their majority share of the DRAM market, "represents a major milestone and the arrival of a new era in technology," IHS said in a report.
DRAM shipments for PCs will drop another 6% over the next year or so, sliding to 42.8% by the fourth quarter of 2013.
"The arrival of the post-PC era doesn't mean that people will stop using personal computers, or even necessarily that the PC market will stop expanding," said Clifford Leimbach, memory analyst at IHS.