to enlighten why the phenom 1100T wouldn't be a good idea as a "silent gaming rig".
one reason is because this baby is a beast of a six core, so what would that mean? the stock HSF will be running loud just to get it's temps low.
so why not just change the HSF then? well one reason would be that its because thats another premium to pay, if the combination of CPU+HSF would breach the difference between the intel's option then wouldn't be going with intel a much more viable option? since intel's counterpart would be running way cooler, and uses way less power and all.
other issues:
another thing is this baby's power consumption, quite a scary thing actually, and a troubling piece for that would be if your PSU is beefy enough to handle the processor.
another problem with recycling your current motherboard and it's other components, first the ram would be a bottleneck for this, a DDR2 @ 800mhz? would be a excruciating bottleneck for such a beast of a CPU.
as for the motherboard i can't seem to trace it's specifications, a whole bunch of results popped, but do notice none of them had AM3 support. wouldn't that be a whole bigger reason as to why switch to intel?
i say instead of scrapping the rig and switching stuff up, just sell the unit and buy a new one, it might even bump your budget as well.
well the decision lies with the one who'll be spending the bucks.