A:Answer I am also a proud HP customer with a 25L and yes, you can use this but I always recommend that if the ram you have is a different speed, change the module but if you want to use then you can, mixed memory modules can work together but at the speed of the lowest module so they all can take data from the man on the bench and he can not cause a collision by not being in sync with the next train leaving to send the bytes over into their spots on the wire. It might be a bit problematic upon the first few boots or not. It is best to make sure you fully power off and even clear your little juice in the power source so that when powered on, it can begin to tell the cmos what is. I’ve experienced a few times of multiple resets to suddenly see it boot and other times it worked right away. So don’t worry too much if it takes any time to get the module up.