Can you mix RAM?

[cam]

I have a MBB-TPX58A- Biostar T-Power X58A LGA1366 motherboard which supports Triple Channel DDR3 800/1066/1333/1600(OC)/2000(OC) MHz.
I have 6Gb (3X2Gb) Tri Channel DDR3 1333Mhz installed.

I'm looking to add another 6GB (3X2Gb) but looking around I've found 1333MHz is more expensive than the 1600MHz so was wondering:
First, if it's OK to use 1600MHz as in the mem type it has 1600(OC), which I take as overclocked.
Second, if 1600MHz can be used is it OK to have the two different MHz installed.

Thanks

[chuckskull]

So long as both are DDR3 it's very rare that you would have a problem. However the memory will only run at the maximum speed of the slowest modules(1333MHz) and you may have manually set your RAM to run at this speed via the BIOS.

[jim]

You can set memory to run at any speed you want using the motherboard. So you can get 2133MHz RAM and run it at 1333MHz. Or you can get 1333MHz and run it at 2133MHz. Of course though, in the latter case, the RAM probably won't support the speed and will just fail/overheat/ignite/explode/wipe out the universe.

In short, that should be fine - as chuckskull says, you may have to manually configure it but hopefully it will just work.

[cam]

Thanks for the replies chuckskull & snootyjim.
As I don't want to wipe out the universe I won't be setting it to 2133MHz

[MattHibbard]

Yes as long as same ddr type.