RAMM

Yes, they will work together, but to make sure they are running correctly, set the latencies in BIOS.

Your current kit is CL5 and the new kit is a slower CL6 one, only the latencies are different, they are both 1.8V.

So , u mean i should set the current kit´s latenci to CL6, same as the other ones, right?

I don't see a list for timings on these but the CAS latency is different and some Intel boards don't like the low profile DIMMs. I've got Intel ASUS and ASRock boards that so far haven't accepted any low profile memory. My AMD builds with ASUS and ASRock support it well.

The only thing I could see is that it doesn't boot or isn't stable. Usually the BIOS will adjust the timings and frequencies if everything is set to AUTO for the memory in the BIOS. Also in the BIOS there is usually an option on ASUS boards that allows you to mix and match memory by down clocking speed and latencies to match the slowest stick in the system.

If it doesn't boot up, just remove them and position them in different sockets, and try again. You will not hurt anything if you handle the DIMMs properly. If it does boot up and appears to work, run a memory diagnostic like memtest86+ to see if there are any errors. Sometimes mixing and matching memory will cause errors if they BIOS doesn't handle them well. Errors can also be bad sticks. But you want to check for errors if it is working and boots. That way your system won't randomly crash in the future... you will know now if you have any issues.

You will have to set them all to the slowest speed of the slowest stick to make it work. If you raise the number on the slower stick to match the better sticks, it won't boot or it'll crash.

Yes, set the latencies to match the CL6 kit.

If you are unsure, you could use CPU-Z to check the JEDEC settings of the memory modules and set BIOS accordingly, you will find the different JEDEC latency settings under the SPD pane.

i don´t think i can do that...don´t know how...
could u explain?

I browsed for your BIOS layout, and it was a bit confusing, but it seems that in BIOS, usually entered by hitting DEL when the PC starts on ASUS motherboards, you should navigate to Advanced > Chipset > Memory Timing Setting

The first four settings are what you want to change according to your ram specification (which you can read using CPU-Z if you can not find them on the memory modules or the package in which they came).