Hello, Where can I find more information about my installed RAM modules? System information shows me only the type of RAM and no manufacturer (which I must know, because I buying new one and mixing RAMs isn't that good). Thanks!
There's no problem mixing RAM manufacturers. You just want to make sure it's the same kind of RAM. If you really want to know what brand you have, open up your Mac and look at the RAM modules.
I mixed my ram, one being Samsung and the other Gskill without issues. Than I upgraded from 4 GB (2GB samsung/2GBGskill) to 8Gb and got another stick of Gskill. You will be fine
For some older models of the Mac Pro's you had to buy ram in paired sets. If that's the kind of machine you have then I'd make sure the pair was same spec from the same manufacturer, other wise I wouldn't worry about it.