With the same sensor, the Alpha 65 has a near identical dynamic range performance to its more expensive sibling, the Alpha 77. On the measured data (www.dxomark.com), the Alpha 65 scores a dynamic range of 12.6EV compared to the 12.8EV of the Alpha 77 at ISO 100.
At ISO 12,800, the dynamic range of the Alpha 65 is 6.9EV, which is almost half its base ISO. This means that the Alpha 65 offers a wide dynamic range at lower ISO ratings, but shows a steady decline as the ISO sensitivity increases, with images tonally flatter when a higher ISO rating is used.
The rating of the dynamic range places the Alpha 65 roughly 1EV below the Nikon D5100, but 1EV above the Canon EOS 60D. In short, the available dynamic range in a single exposure is in line with the competition.
The sensor of the Alpha 65 is more densely packed with pixels than its competitors, which means they are smaller and collect less light individually. It is impressive, then, that the camera matches the performance of other, less densely packed sensors.