I have 4gb corsair 1333mhz ram on my mobo and now I want to increase it to 8gb. I m thinking to buy gskill 4 gb 1600mhz ram. Will it be ok with my corsair ram as it low mhz?? Or should I replace my corsair ram and get both new 4gb 1600mhz rams?
Yes it will be fine. although its not recommended to mix and match different company RAM modules. the faster stick will automatically run at lower clocks.
In your motherboard (i.e m5a88-m) you can run them in 2 ways.
1. Put those RAMs in A1,B1 (first two) slots and they will run at their individual speed.
2. Put those RAM in A1,A2 or B1,B2 slots (color matched) and 1600MHz module will suto down clock to 1333MHz.
Bother config will run.
In my point of view, you should run the #1 method mentioned by me.
OS 32/64bit ?
However you do it, all modules will run at the lowest clock speed.
If OCing ? Get new 1600 ones
or
else just add another of the ones you already have and make sure they are the same.
As above answers r not satisfying i think I'll have to discard 1333mhz ram and put both new 1600 ones.