Last week was good for NAND flash memory chips with prices rising as much as 15 percent in the spot market.

RBC Capital Market’s Doug Freedman, who tracks the semiconductor market, observed that NAND memory chips were closing the gap with DRAM in terms of pricing. Prices of DRAM chips also rose 8 perent during the week, and it has risen about 40 percent during the quarter so far compared to a rise of 10 percent for NANDs in the same period.

Freedman said that the price increases are a function of both demand for flash in solid-state drives for consumer and enterprise devices, and also the effect of some curtailment of supply by Samsung Electronics.

 “In our view, we believe that NAND strength in the week could partially reflect a move by Samsung to move customers towards allocation buying, as the Samsung’s bits are becoming increasingly absorbed by internal mobile ramps, particularly its Galaxy S/Note family,” he said.

In the case of DRAM chips he said that pricing momentum is being driven by “planned supply cuts, slowing bit production given node migrations, strength in the mobile market with LP mobile DRAM loadings moving higher in new smartphones and conversion from traditional PC DRAM to higher growth mobile DRAM and specialty DRAM.”

 Freedman has an Outperform rating on both SanDisk Corporation(NASDAQ:SNDK) and Micron Technology, Inc.(NASDAQ:MU) and a $65 price target on the former and a $10 target on the latter, but he likes the upside in SanDisk better.