I have this primer which is targetted for certain gene. Since I'm using the relative standard curve methods, plate that is available in my lab is only 48 wells. I have a quite large of samples that I need to test thus I've run them few times now. I read somewhere that unknown sample should be run in with their standard, so each time I run in a new plate I also make a new standard; hence, I've got few of amplification curve by now.

However, I noticed that their efficiency is quite different... I know that sometimes in these wells I got a high standard deviations, might be because of my own skills but, regarding the efficiency should they be similiar? Cause sometimes I got like 79%, and then 80%-ish something. And I also ever got above 110%.

Does efficiency also depends on the DNA extract quality? Cause for the rest of qPCR mixture I think it was just the same.