I don’t agree with the shop, but they just try to avoid a return on one of the components. Unlucky for you (and many others) modern DDR4 and DDR5 motherboards and CPU’s are picky with memory. Special when getting above 3200MTT (1600MHz). To get the intended 3600MTT (1800MHz) you will need memory that supports it. And there comes the trick, we do not know if your memory supports 3600MTT, because it can be Intel compatible memory.
Some manufacturers label their Memory with AMD or Intel compatible signs. Example, two identical sets are under their hood not identical, so always look at the PARTNUMBER when you order, that partnumber can be picked from the motherboards manufacturer site on their compatibility list for the specific motherboard. If the partnumber is not listed there, your supplier is correct, max 3200MTT only. So G.Skill ….. or Kingston ….. does not say it works, because you might get unlucky by selecting the wrong memory twice. Even with Corsair it can be more complex because they have Version 1.1, 1.4 or whatever, and some work, some won’t even when having same partnumber.
Note this
is not an AMD related issue, it also applies for Intel 10…/11…./12… lines of CPU and go above 3200MTT (1600MHz).
Example, I made a mistake ordering a 2x16GB 4000 MTT CL16 set for Intel (found out later it was for Intel because I had same issue as you), because the CL is more important to me. I choose it to run on 3800CL16 instead of returning it and wait for 3 weeks to order because it is very difficult to get.
So first action is, try to find a set that matches your HW compatible list of your motherboard.
And if you want future expansion. Replace it with a higher capacity set then rather expand number of modules and sell the old set. Mixing sets, even with same partnumbers is a bad idea, as is using more than 2 DIMM slots.
if the set is listed on your Motherboard manufacturer list, and listed as tested with the desired frequency, then contact your reseller, because it should work! And use the list of your motherboard. Example if you have a Gigabyte Gaming B550 and you use the list be of a Gigabyte Gaming X570 it might not work.
