The P5G41-M LX motherboard natively supports up to 1066 MHz DDR3 memory. 1333MHz memory will require overclocking.
Using memory search/configurator at most major memory manufacturer websites, most of these manufacturers don't have a listing for the P5G41-M LX motherboard. And for the few manufacturers that list this motherboard, the manufacturers have listings for DDR2 memory only, there are no listings for compatible DDR3 memory, unfortunately.
The only compatible DDR3 memory at 1333 MHz found is on the motherboard QVL. It is Kingston 2 GB @ 1333 Mhz, part number
KVR1333D3S8N9/2G. It is available
here.
It is highly likely there are other compatible DDR3 memory available, but it is unknown which specific models/part numbers are compatible with the P5G41-M LX motherboard.