Running two different types of ram

[SINDRONE]

Hey,

The PC has two different types of ram in at the minute, 2 Elpida 1gb sticks and 2 Corsair 1gb sticks; i've used the pc for 3 years and just assumed that having two different types of ran was fine, a friend of mine's just told me that they won't run in dual channel mode because they're not the same sticks, so basically what i'm asking is just how much slower is it compared to having the same type of ram?

 

[SINDRONE]

Haha, thanks for letting me know, and no, he works in plain clothes XD

 

[SINDRONE]

Thanks for the help, it's my old pc, 6 years atleast i'd imagine. Planning on giving it to my Mum to replace her even older one. Just wanted to see if I'd be better of giving it to her with just the 1 kind of ram