Mac Pro Memory: A Hot topic - Part II

The huge heatsink covering RAM modules installed by default in Apple Mac Pro have been the subject of numerous rumors, hypothesis on the web; especially due to its size.

Many users have questioned the real benefit of heatsinks sitting on the FB-DIMM found in the MacPro; making those RAM modules looking like those modules highly priced because supposed to better perform when overclocking them.
One should not forget that the FB-DIMM is designed differently than the current DDR2 memory.

If the RAM chips are indeed standard DDR2, a small processor located in the middle of the FB-DIMM module is controlling input, output, as well as ECC and buffering. The main heat released by a FB-DIM module is originating from this processor.
However, as shown on the photo below, a Samsung FB-DIMM module sports a much smaller heatsink than the Apple's one.
Apple has released information concerning the reason behind this huge heatsink: silence.
Having a large heatsink featuring a important exchange surface will dramatically improve cooling efficiency while reducing the air flow required to keep RAM modules cool. So, fans can rotate with a lower speed, keeping the machine silent.
So using non Apple FB-DIMM RAM modules might simply translate into higher working temperature and consequently a noisier MacPro. The raizer cards contain temperature sensors.
Already, some US RAM module providers, such as Transintl are proposing RAM modules following Apple's specifications.

Their heatsink looks really similar to Apple's one. However, one will need some tests, feedbacks and in-depth analysis to get a more precise idea of the real specifications required to keep the MacPro silent while maintaining RAM performances.
To conclude, after switching off the Mac Pro, Apple recommends waiting 5 to 10 minutes before touching RAM modules. Apple is even mentioning that overheating of RAM modules can be the source of system instability, and should be check by Apple Certified Center/Support when getting a Mac Pro for service.