a99 low-light

I was looking at full frames. I am disappointed with Sony. I am looking at DxOMark for the a99.

• a900 DxO: ISO1431 
• a99 DxO: ISO1555
• D600 DxO: ISO2980

Does the a99 really have half the low-light performance of a modern full-frame, and on-par with Sony's 2008 model? Is it really a full stop behind Nikon's budget model (which is also as good as or better at resolution, lens selection, color depth, dynamic range, has many more focus points, much battery life, and only 0.5fps lower shooting speed)?

I like IBIS+fast primes, but that's not bridging a full stop gap and a $800 price difference... If DxO is correct, Sony has not released any viable full frames in a long, long time...