managed to find the GTX 580 on Nvidia's website and it looks like the big green slipped its existence on the 3D Vision System Requirements page.
According to the recent rumours, the Geforce GTX 580 should be based on 40nm GF110 GPU that should have 512 CUDA Cores, 2GB of GDDR5 memory and should appear sometimes by the end of this year. Nvidia has planed to push this card against AMD Cayman based cards.
The Geforce GTX 580 appeared here
, but we are pretty sure that Nvidia will take it off in a matter of minutes. In case that happens, the guys from Techconnect.com have a screenshot ready. You can find it here