Weird freezes after startup

[nobbypop]

Ho folks,
I've got a weird problem here.

Nearly every time my HackMac fires up, it surely will freeze after some minutes.
If the machine was up, let's says 10minutes without trouble, or has been reset and rebooted, it runs stable with ABSOLUTELY NO issues at all!

I discovered that there are signs that this could be related to network setup/traffic.

My setup is as follows:
- Gigabyte Z77-DS3H
- Intel Core i7-3770K
- Corsair Vengeance Blue 16GB DDR3-1600
- Asus Nvidia GTX670
- Sonnet Presto Gigabit Pro
- Pro-Ject DAC Box S USB
- Mountain Lion (up to date)
- Chameleon 2.2r2234

AFAIK, there are no log entries indicating anything.
Any suggestions?

 

[nobbypop]

After months of absence here in the forum, I need to push this post, because the problem persists.

It could, of course, lead to thermal problems, because after 3-4 minutes or so, everything works fine.
Doesn't anybody have similar problems?