The Samsung 840 Pro is an excellent evolutionary improvement over the company's previous-generation 830 Series SSD. The included five-year warranty underlines Samsung's confidence in their new product, and the thin 7 mm form factor makes this drive a perfect match for Ultrabooks. We see around 2% higher real-life performance if compared to the 830, making the 840 Pro the fastest SSD in our test group - tied with the OCZ Vector and the MX-DS Turbo, which uses SLC flash chips and costs twice as much. Looking at the synthetic performance section, we see superior read performance, but write speeds are lower than even some SandForce-based drives, and the OCZ Vector.
Our Steady State Performance Testing reveals that while Samsung has improved things considerably compared to the 830 Series, easily surpassing SandForce-based drives, the 840 Pro is unable to match OCZ's latest Vector SSD. Moving on to MySQL Enterprise testing, the 840 Pro doesn't shine until it's subjected to a concurrent user count of 48 and above, after which it consistently delivers slightly higher performance than most other drives, albeit a tiny bit less than the 830.
With a price of $250 for the 256 GB version, the 840 Pro is quite expensive, but ends up $20 or 10% cheaper than the OCZ Vector. You can't go wrong with either product if you are in the market for a high-performance SSD. More price-conscious users should also look at the aging 240 GB SandForce drives, which come at outstanding pricing right now and are not much slower. Technically, the 840 Pro should be very cheap to make for Samsung as all components, including the flash chips, are provided by Samsung itself, so we may see some price drops with more competition in the high-end market.