за вот такие вот решения:
"The Xbox is supposed to find out the highest clock speed the RAM chips can go and run them at this frequency - this is the reason why some games don't run as smoothly on some Xboxes as on others. So the startup code in the secret ROM has to do a memory test, and if it fails, clock down the RAM, do another memory test, and if it fails again, clock down again, and so on, until the test succeeds or the RAM cannot be clocked down any further."
//from
http://www.xbox-linux.org/wiki/17_Mistakes_Microsoft_Made_in_the_Xbox_Security_System