At all depends on what its scanning, if its scanning say 4 HDDs full with music and apps etc , then thats not bad. Longest I have done on PC,abought 40mins I expect.
still no competition for me, i did one using NOD32 (in depth analysis on local drives) starting after 4pm until the next day, check more on my thread HERE
edit : 1 hard drive totalling 150GB / 2 partitions