Single box freezing issue. New computer

[luxlunae]

I have a problem that one of my boxes keeps freezing in instances. Tank box, nearly always on trash. The frame rate isn't dipping first or anything. The cpu is spread evenly across all characters (per the default settings) and the only other difference between the tank box and the slaves is the graphics settings. Running on 16 gigs of memory, nowhere near maxed out, and using gtx 570 which doesn't seem to be taxed until the moment that one box crashes. that box cannot be closed except through the processes tab of task manager.

My tank settings are hardly maxed out either:

/console groundEffectDensity 15
/console groundEffectDist 1
/console horizonfarclip 2112
/console farclip 1250
/console skycloudlod 1
/console smallcull 1
/console skycloudlod 1
/console projectedTextures 1
/console waterDetail 2
/console rippleDetail 2
/console reflectionMode 3
/console particleDensity 80
/console weatherDensity 1
/p High Graphics

versus

/console groundEffectDensity 16
/console groundEffectDist 1
/console horizonfarclip 2000
/console farclip 1000
/console skycloudlod 1
/console projectedTextures 0
/console waterDetail 0
/console rippleDetail 1
/console reflectionMode 0
/console particleDensity 80
/console weatherDensity 0
/p Low Graphics

Basically I have a new machine that shouldn't have any problems... and it doesn't' except for these crashes.

Help!

Edit: one other thing, my running load for the cpu is abot 35% normally, with each box taking 5-8%... when the tank box freezes it shows as 24-25% on the task manager.