Hi Sergey ! There are a few things that can cause this .
What hard drives and how are you recording ? ( Is important what chris ask you , more detalied system report would be helpfull )
Make shure to have all your drivers upated specially the chipset drivers .
And last make shure to have all the windows optimizations done .
http://avid.force.com/pkb/articles/e...ndows-10-Guide