First of all, make sure the two DIMM sticks are put into the slots labelled A1 and B1, or A2 and B2. If this is correct, then try putting the DIMMs into the other slots - in other words, if you are currently using A1 and B1, try them in A2 and B2.According to the fact you mentioned above so I don't need to replace my memory and this is actually a very good news for because me I don't have enough budget for it. But then how should I get to 3600MHz of speed? is there any solution to reach to that speed? Even if its manually done I'm okay with it.
Somewhere in the BIOS will be an option called 'XMP High Frequency Support' - it defaults to Auto, but you can try setting to Level 3. This option controls the clock speed of the Infinity Fabric connection system in the CPU. At Level 3, it sets it to 1800 MHz, which would match an XMP 3600 MHz profile.