I have just swapped my macbook pro 13inch (new) due to a faulty screen. Both have the same hdd's (toshiba) 5400rpm but the new one is much slower. On the first one, i was getting 70MB read/write tops using black magic speed test. On my new mac, i'm getting just 35MB read/write. There is no background HDD activity, nothing showing in activity monitor. Why is it so slow??