DDR3L modules are backwards compatible with DDR3 by design.
Manufacturers use the same integrated circuits for DDR3 and DDR3L. The highest quality ICs are tested for operating at 1.35 volts and are branded as DDR3L if they run properly. Other than that, there’s no difference between them.
yes it is correct, that they should use the same Chips. So from a functionallity point of view it is really just the same compatibility issue as with DDR3 from one vendor to another vendor (or even just for one die shrink to the next die shrink).
JEDEC defines that the DIMM needs to be backward compatible. So if a JEDEC compliant DIMM is operating at 1.5V should be tested and verified from the vendor. But not too many DIMM vendors really state that the DIMM is JEDEC compliant.
E. g. I have seen DIMMs with devices not supporting specific CL that they would need to support to be JEDEC compliant ..
And in this case thre is no need that the DIMM really is backward compatible (even if it is just a question of Speed, or reliability over time).
Even standard DIMMs are theoretically interchangable, there are many compatibility issues between motherboard, controller and DIMM out there .. and DDR3L will not make it better ..
Guess thats the usual difference between theory and praxis ..
and so I prefer to look at the DIMM spec and at least verify that the 1.5V is a supported voltage on a DDR3L DIMM if I intend to use it in a DDR3 System…
Hermann