[halcon_rojo]

gracias Alvaro por tu interes, tal vez se deba a algun 'error' en el archivo de texto, de todos modos mi pregunta es si cargaste el archivo de 10Mb en el TStringList y lo recorriste? o solo lo cargaste?
acerca de mi otra duda de por que me demora tanto la carga y al tener en mi codigo una llamada repetitiva del ProcessMessages encontre este comentario:

In your loop you need to add a call to the Application.ProcessMessages method. This will allow your application to process Windows messages, including those generated by user actions. There are two significant caveats. First, since Windows messages often translate into calls to event handlers your program may begin to do things at inappropriate times. Make sure that the user can't initiate actions that will interfere with the loop while the loop is active. In particular, note the following sentence, taken from Delphi 3's help file on TApplication.Terminated: "For applications using calculation-intensive loops, call Application.ProcessMessages periodically, and also check Application.Terminated to determine whether or not to abort the calculation so that the application can terminate." The second caveat is that calling Application.ProcessMessages can be relatively expensive and may slow the program. In a fast (tight) loop you may not want to call the method on each iteration. If you only want to update the display and not handle user input you can use the Update method (Delphi 3 and up) of the control covering the part of the display you want to update. Remember that this will also slow down the loop!