does it matter if which slots i use for dual channel?

Solution
rtfm ;)
recommended slots are a2 & b2, but if the modules are working fine and you don´t have problems, you can stick to a1 and b1

install memtest86+ to thumb drive and boot from it to verify that all is ok

in CPU-Z you should look up, if dualchannel is enabled
rtfm ;)
recommended slots are a2 & b2, but if the modules are working fine and you don´t have problems, you can stick to a1 and b1

install memtest86+ to thumb drive and boot from it to verify that all is ok

in CPU-Z you should look up, if dualchannel is enabled
 
Solution