AFAIK the Pro SSD does not need the update as it has MLC nand and not TLC like the EVO does.
On the EVO you'll need Windows to run the Magician software. That makes it very easy to
run the firmware update for the EVO. You can also do some other very impressive things
with that. Makes it very easy to make a Ram disk to speed up your Windows performance.
They call it Rapid Mode. Makes it unnecessary to raid two SSDs together for more speed.
http://www.samsung.com/global/business/semiconductor/minisite/SSD/global/html/support/downloads.html
If you already had Windows installed to an older EVO SSD with your data already on it, here's what Samsung recommends:
The firmware update is recommended to users who may have experienced any drop in read performance of the mentioned drives. Running the software packages provided will first update the firmware(840 EVO : EXT0CB6Q, 840 EVO mSATA : EXT42B6Q), then scan and calibrate all existing data on the drive.
They call this the EVO Restoration software. The download link is right below the Magician Software. Looks like
there is also a DOS versions you can use for OS X installs on an EVO SSD. This will update the firmware and calibrate the existing data on an older EVO drive that has slowed down.