The way I see is in ED the main loss of pattern was due to having too much magical energy pumped into one's being, thus causing one to explode. Where-as cyberware drains magic, or rather causes holes to be poked in one's being. It does similar damage as in ED but w/o adding the extra mojo for the boom at the end.

Also ED is on a higher mana level than SR. SR is going deeper into the mana as time goes on where ED was coming out of it. So that might account for much of the difference.