Elgato HD60 Pro - Speeded up footage, audio/video desync, artifacts etc.

Hello :) Two days ago I've bought the Elgato HD60 Pro. I've decided to write here, because I can't find solution for some issues. When I start recording everything is ok, but after couple minutes of recording, video starts to be corrupted. I've tested many different setups, but nothing helps. My rig:

• Motherboard: MSI Z97 GAMING 3
• Processor: i7 4790k @4.0Ghz
• Graphic card: MSI GTX970
• RAM: 16GB 2133Mhz
• HDD: Seagate 1TB, SATAIII, 7200RPM, 64MB cache
• SSD: Plextor M6V 128GB SATA3
• System: Windows 10 Pro
  I have the newest version of Elgato software, and newest drviers for Elgato HD60 Pro. I'm recording to my HDD. Some links: My Elgato setup: http://imgur.com/mO1MUkq

First part of recorded gameplay (without any lags etc.) https://www.youtube.com/watch?v=WToe9i7rNfc

Second part (after couple minutes of recording) it's not edited by me, that's how Elgato software recorded and exported it to my HDD https://www.youtube.com/watch?v=YK64FGH_lkw

I would be very grateful for your help. Thanks in advance.