fume 4, cache writing slowdown

[finalightvfx]

trying out fumefx 4.0 before putting into production. when creating a new fresh test scene, ffx sims fast as expected (in a simple high spacing test scene). then test scene is saved to disk, and upon a resim, the cache writing is extremely slow. something happening when fumefx 4 has a filename to reference?

running win 7, simming to local drive. no previous slowdown with fumefx 3.x