Sprint/Virgin Mobile normally have certain hours were they're data speeds are unusable; the time/hors might be(probably) area specific though. For me in St.Thomas, US Virgin Islands, the slow down time when it's hard to even do web browsing is from 8:00pm to 11:00pm. The minute(and I do mean the minute) the clock touches 11:00pm speeds have a major sudden boost. From 8pm to 10pm, I'm normally getting 10KBp/s, while early in the mornings I normally get up to 3Mbp/s; though most of the day I get around 1Mbp/s.