What kind of distortion is this?

I really love the crunchy, growly synth distortion on this track and would love to know how to replicate it. Doesn't seem like anything I've done with Ohmicide and I'm wondering if it's maybe that kind of growl you get by modulating a cutoff filter with a very high frequency? It's throughout the track but there's a good example of it if you fast forward to around 3:10. 
 

It is not distortion in the usual sense. It sounds like ring mod maybe or yes the oscillator frequency itself could be modulated by another frequency. Filter might be getting some of this modulation source too.
 
There is hint of that metallic ring mod sound in there. It does not sound so much like an effect but it may be happening right at the source.
 
A modular synth will get you that sound.  I am sure some of your synths will allow it. Some LFO's can run real fast too almost up in audio freq range. The modulation frequency is lower than you think though.
 

I'd hazard a guess there is an awful lot of audio frequency modulation of pretty much everything going on. Detuned oscillators running against each other, filter modulation (sawtooth waves can have this kind of effect) and maybe ring modulation between the detuned oscillators as well.

Plus some light overdrive and creative use of reverb or very short delays.

But that's just a guess.

I grabbed a synth sound here and ran a few distortion sim boxes on it, sharke. It sounded really close with a Heavy Metal pedal and a tube screamer. Add a tube saturator or tape sim and you may even get closer. I get a little dirt out of those Waves channel processors which do a nice job on stuff like this.
 
There's also an old Sonar plug that may help get it...but I'm not at THAT pc to find it. Try the blue tubes driver and see how that works for you.
 
-Danny