$alphatest
From Valve Developer Community
$translucent can sometimes lead to rendering errors, such as a surface behind an object being drawn in front of it or two nearby surfaces "fighting" to draw when viewed from a distance. If this happens you may want to consider using $alphatest instead of $translucent.
$alphatest is also far cheaper than $translucent, but reduces the bit depth of the transparency - i.e. creates jagged edges and sacrifices fine quality.
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VMT syntax example
// $translucent 1 $alphatest 1
