Im currently using a 40mhz '040 in my desktop a1200 and I find the fan itself isnt too important. If it fits and works it'll probbly be ok, but the problem is ventilation. Id suggest either removing the trapdoor plastic cover or cutting it to provide good airflow. In both cases the a1200 needs to be raised a little compared to normal (larger rubber feet should suffice). It also doesnt hurt to try to prop up one croner of he accelerator if possible to stop it dropping and keep it a little higher (again for airflow).
