Mixing ram, same manufacturer...?

I have 2gb of A-Data Vitesta Extreme, and they don't sell it on Newegg anymore. Was thinking about getting another 2gb of A-Data Vitesta (not extreme) to save 25 bucks from getting a new 4gb set. They bothrun at the same timings, PC6400, etc. Can I do this stable-wise? I'd think it'd be fine but you never know...

As long as they have the same specs they should be fine. The size doesnt matter as much as timings,brand,etc...

Ive had problems in the past with ram that was differnt timings and companys. Its always good imo to just buy a set of ram instead of just one and mixign it. But if its the same brand and same timings you should be ok bud.