50D Noise and Firmware
I don't know if the firmware has much to do with the noise in the high ISO images. The real culprit is Adobe Camera Raw! I tested the ACR against the Canon Photo Professional raw conversion. The Canon converted images are very clean, even at ISO 12800! I took a shot at 12800 and converted the raw file to JPG without any adjustments. I then took the same raw file and converted it to a DNG and opened it in Adobe camera raw and saved it without adjustment. OMG what a difference! The JPG converted by the Canon software was much cleaner than the file converted by Adobe. I then put both images through Neat Image and the Canon converted image was good enough to print a 5x7. The image converted by ACR was unuseable.