Macbook Air 2011have two different models n two different performance of SSDs?

When you head to Apple's online store to configure your MacBook Air, you'll find options to increase processor speed or SSD capacity -- depending on the model you select, of course. There's no mention of flash drive speed, however, though it's now clear that not all SSDs are created equal at Apple -- not only when it comes to capacity, but also performance. Jonathan over at TLD discovered a fairly significant discrepancy when benchmarking both MacBook Air models over the weekend. The 128GB Samsung SSD in his 11-inch Air was able to achieve 246 MB/s write and 264 MB/s read speeds. When he switched to the 13-inch model, however, speeds dropped to 156 MB/s and 208 MB/s, respectively, using that notebook's 128GB Toshiba SSD. We compared speeds on two generations of 13-inch models, and confirmed Jonathan's findings. During our tests, the 256GB Samsung drive in our older model achieved 214 MB/s write and 251 MB/s read speeds, while the 128GB Toshiba drive in the new MacBook Air scored 184 MB/s and 203 MB/s during write and read tests, respectively.

According to reports from AnandTech, a number of newly manufactured MacBook Airs contain a different model SSD than what has been used before. This new SSD, identified as model SM128C, is reportedly almost 25% faster in read speed and 20% faster in write speed. Additionally, AnandTech confirms Native Command Queuing support for the SM128C, which could be responsible for the significant increase in performance that the new model brings. Although unconfirmed, the model naming scheme hints towards Samsung as the manufacturer, especially considering that the SM128C is performing at similar benchmark scores to the Samsung 470 Series of SSDs.