Usually I get about 2.5 Mb/sec download, which is bad enough, I understand many DSL connections achieve up to 8 Mb/sec. But then it will clog up and I'll get only 20% of what I was getting just a minute before. The performance fluctuates throughout the day and night, but the most likely time to get the really slow speeds is early evening, so it seems correlated to peak hours.
My understanding was that a DSL is a hardwire connection to the internet. Its bandwidth should not vary. I highly suspect AT&T has developed a scheme that continuously re-allocates bandwidth among active users, "robbing Peter to pay Paul". Not all of their customers use the internet at the same time. For a certain number of users, the re-allocation would be unnoticeable. But the more users on the grid, the more performance would have to suffer. The temptation on the part of AT&T would be to service as many customers as possible for a given hardware investment.
This is not unlike the way banks originated the process of "fractional reserve banking", where they would fraudulently issue paper receipts for gold far in excess of the gold they actually possessed. Of course, the banks eventually managed to "legitimize" the practice and eliminate the obligation to redeem in gold at all.
Is anyone else experiencing fractional reserve bandwidth? Is this what you paid for? How might the large internet providers seek to legitimize the practice, once it becomes known?