ASROCK Q1900M Manual Del Usuario página 11

2.1 Installing Memory Modules (DIMM)
This motherboard provides two 240-pin DDR3/DDR3L (Double Data Rate 3)
DIMM slots. If only one DIMM module is installed, please install it into DDR3_A1.
It is not allowed to install a DDR or DDR2 memory module into a DDR3/DDR3L
slot; otherwise, this motherboard and DIMM may be damaged.
The DIMM only fits in one correct orientation. It will cause permanent damage to
the motherboard and the DIMM if you force the DIMM into the slot at incorrect
orientation.
Q1900M / D1800M
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