Slow Operation

[jason.luka]

After firmware update models T20, T22, T26 and T28, for versions 2.70.0.140.rom, 6.70.0.140.rom, 7.70.0.140.rom and 9.70.0.140.rom, the phones after a while you start using to be slow in the operations of incoming and outgoing calls, late delivery of audio, it is necessary to restart the phone to return to normal operations. Having to repeat the restart the device several times for periods varidos (examples: some tevem restart after 2 hours, others after six hours and other after days of operation)
There is no set time for this problem to happen and does not happen on all devices in the same moment.
What can I do to get around this problem?