RAM Speed make a difference?

[Biz.Kid09]

I currently have 1 x 2gb of 6400/800 in my pc, i have been offered some 2 x 1 gb 5300/667 for a good price.
Can i simply stick the 2 667's in and it will work or does all the ram have to have the same speed?
Thanks guys,

 

[rxmac]

I assume you are going to run both sets?

The ram doesn't need to be all the same speed, the bios should detect the slowest speed memory and run it all at that speed.

More important is the voltage rating make sure they are rated the same / very similar and set it manually.

 

[Cookeh]

I assume you are going to run both sets?

The ram doesn't need to be all the same speed, the bios should detect the slowest speed memory and run it all at that speed.

More important is the voltage rating make sure they are rated the same / very similar and set it manually.

Quoted for truth.