Adding RAM with lower clock memory

[ToasterBoogaloo]

I just bought a laptop with 8gb 3200mhz and it's just not enough for me, but since I used all of my money to buy this laptop I can't buy a memory stick anytime soon and I'm gonna move out next week, I do have a 2666mhz from my old laptop, is it okay if I add that alongside my 2666mhz? what kind of performance impact i should expect?

[mariushm]

Yeah you can add it, both sticks should run at 2666 mhz then 

Performance loss .. depends on CPU and more noticeable if you use integrated graphics playing games. Even then, I'd say less than 5% - you'd gain a lot from having dual channel memory and the extra capacity so overall it should feel better.