Attiny85 and 16x16 ws2812B Led Matrix controll. (256 leds) issues

I'm trying to run 256 leds (a pixel matrix made of ws2812B leds) from my attiny85. My arduino doesn't have any problems with this code, however, my attiny doesn't seem to support anything over 128 pixels. Power isn't the problem, connections aren't the problem either. My assumption is that the Attiny85 just doesn't support any more than 128 pixels. (which seems strange to me). any thoughts?

Thank you in advance!