Nope, you won't void your warranty doing this. If you experience problems in the future and call Apple for help, they will ask you to remove the 3rd party RAM as a first step. Other than that, you'll be fine.
But if you remove all your Apple RAM and have to return it for service you must remember to put some Apple RAM back in or it will be invalid under the warrenty. (So don't just stick it on eBay.)
But if you remove all your Apple RAM and have to return it for service you must remember to put some Apple RAM back in or it will be invalid under the warrenty. (So don't just stick it on eBay.)
that's my experience based on a G4 tower bought from an authorized reseller who upgraded all of the ram with 3rd party stuff before the computer was delivered. Later there was a problem and Applecare's first thought was that possibly the 3rd party ram was bad. The problem turned out to be completely unrelated to the ram though and the problem was fixed under apple's warranty.
The replacement of the original ram didnt effect the warranty at all.
of course if the 3rd party ram HAD been the problem, it wouldn't have been covered by apple's warranty