Problem for giroud was that his best players to play with last year were pace guys podolski and Walcott who never played together due to both of them being defensive wastemen.
Now we have hard working pace players who are a threat on both sides (Sanchez and Ox) the olly has looked better as his pace isn't shown up as often due on other options and opponents can't push up on him due to the pace threat. It is no surprise he is banging them when his weaknesses are mitigated by his teammates.