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Comparing the Mercury Extreme Pro 3G 480GB to 240GB Model
Be sure to also read Special Report — Real World SSD Performance. Not all SSDs can withstand heavy use, or even moderate use, so caveat emptor. See also the test of the 400GB Extreme Pro RE.
In July 2010, OWC released a 480GB model of its Mercury Extreme Pro line, which expanded the line to 60/120/240/480GB models. All models are a fantastic choice in a MPG Pro Workstation or MPG Pro Laptop. But for RAID-0 striping stick to the 100/200/400GB models.
View all the models at the OWC web site.
Performance 480GB vs 240GB
I used DiskTester to test the drives, part of the diglloydTools software suite. The fill-volume command is a demanding and revealing test, and can be relied upon for true drive behavior because it tests the whole drive.
Both the 480GB and 240GB models are outstanding performers. This performance is not far off the absolute maximum limit of the SATA bus. The 480GB model was just a hair faster for writes (by 1.1%), but both drives are the same speed for reads.

Read and write performance across the entire drive can be seen below. Curiously, the 480GB model shows periodic downward spikes in performance. This is not the case with the 200/240/400GB models. I spoke with OWC about this, and the issue has been tracked down to a recent Sandforce firmware change. OWC is reverting to the previous firmware until Sandforce explains the new behavior.
Unlike a hard drive, solid state drives do not slow down as they fill up! Click for a larger graph.

Conclusions
The Mercury Extreme Pro 240GB and 480GB solid state drives look to be the model of choice for many users. At a very competitive price, and a selection of capacities to suit varying needs and budget, any Mac user can look to these drives for a game-changing performance upgrade.
These Mercury Extreme SSDs aren’t just fast, they hold up to abuse, and thus stay fast over time.
Need high performance in a Mac Pro or MacBook Pro?
Check out the MPG Pro Workstation and MPG Pro Laptop.