Which RAM frequency?

[chrismani]

I have a pretty old desktop pc and it uses DDR2 Ram. I was going to install 4GB ram since ddr2 is getting phased out around the world and I want to pc to last some more.

On the motherboard its written DDR2 667

I was wondering if I can install a ram of higher frequency in that and if my motherboard will use that whole frequency?

I don't want to install a higher frequency if my motherboard can use that frequency because I will be wasting money.

It is Acer Aspire

I am sorry that I don't know about rams and it would be a great help if anyone can help me out and tell me more about these frequencies.

I tested a 800 something ram on it and it worked but is it using all the 800 mhz or just 667 and idling the rest?

Thanks

 

[nna2]

if 800MHz runs, use 800MHz ram... it should run faster than 667 ram, and you can only have one frequency installed, so its either 800, or 667... meaning if you have 800MHz ram installed it will run at 800MHz