What the hell is a Nova Blast and who's Martyna?
Me.
As Malag said above, Nova Blast is the white-out effect that Slasher uses, as well as the 'expanding ring of light. These will lag the EC to no end as well as potentially crash it or require a restart due to your screen turning black.
There is a lesser nova blast that is an expanding nimbus of fire (looks like flamestrikes)- These are currently used for treasure guardian locked objects during EM events. If those happen often enough the EC will become turn based in its slowness and eventually lock up.
Presumably this is caused by the gaping memory leak in the graphics processing which they have known about since November and have done nothing to fix.
If they can fix the blackness issue, they should be able to fix this if they get the act together...