Most forum users know that at 9am GMT the vendors; Auction House; Bank will be slow to open and searching/repairing/selling/depositing or retrieving items takes an inordinate amount of time.
However newer players will be less aware invariably call it lag; blaming the game and either quit/logoff whilst it occurs or just generally build up a bad impression of DDO and its servers.
To the best of my knowledge the cause is actually scheduled database maintenance.
I say that because In Europe the exact same circumstances were escalated to the admins and they advised it was a database-related task. Shortly afterwards the task was disabled by Codemasters because players complained about the effect it was having. It came back one time after maintenance and again it was made clear this was database-related and again disabled - never to reoccur and neither did the vendor slowness.
Presumably Turbine still need to run this process on the F2P servers due to greater numbers of players, leading to higher levels of fragmentation so there is little point requesting it cancelled as one would hope they are aware of this situation. I do feel something needs to go out to logged-on players over what may be important technically for performance but to players is seen as a major annoyance.
If the job cannot be delayed until the servers are offline for scheduled downtime I would suggest a timed world broadcast go out on all servers announcing that servers are performing online maintenance; that players don't need to logoff but the vendors; AH and banks will run slowly during this period for up to 30 minutes. Additionally advise that they may also experience slightly longer zoning during this time.
Users will be made aware it's not the client; network or game lag but are informed of the cause along with how long it will last.
Players can work around this allotted maintenance time and use the vendors/bank/AH beforehand and hopefully they won't use these facilities as much, reducing the time online maintenance takes place somewhat.
Less players restarting the game believing it's them or quitting because they don't enter instances in the usual amount of time.
Time taken to script a timed world message to coincide with the database scheduled task.