Why high ISO advantage for A77 over A65?

[cynan]

<div id="linkdxomark">This a comment for <a href="http://www.dxomark.com/index.php/Cameras/Camera-Sensor-Database/Sony/SLT-Alpha-77">this page on the website</a></div>I posted something similar on the A65 page, but I was wondering if anyone could shed some light on why, given both are using the same sensor, that the A77 scores 801 in high-ISO while the A65 only scores 717. I understand why the A77 might score higher overall due to the lower ISO range, but not why it would be better in low light.

Looking at the NEX-5N vs the NEX-7, the high-ISO performance difference isn't as great (1079 for the 5N vs 1016 for the 7) and they are using sensors with significantly different resolutions.

So why such a big difference in high ISO for the A65 vs A77?

[cynan]

Might it be due to the faster max shutter speed on the A77 vs A65? Perhaps this makes a higher ISO setting more usable when using the 1/8000 shutter setting?

[TCav]

I don't see an advantage. From among the A77, A65, and NEX-7, all of which use the same sensor, the A77 and A65 have almost identical scores for SNR 18% and Dynamic Range. You may also notice that the SLTs' scores are a little bit shy of the scores for the NEX-7, no doubt due to the light lost to the PDAF system via the "Translucent Mirror".