<p>Michael, when it comes to high ISO performance, the D810 is far superior to any DX body.</p>
<p><em>"Users forget that in or</em><em>der to get the low noise benefits of the D810, you need an excellent, heavy duty tripod and technique."</em></p>
<p>Excellent technique will certainly help with improved image quality (with most bodies regardless of format), especially with very high megapixel bodies, but the low noise benefits really come from the larger sensor size.</p>