v3d frequency goes to zero

[Kosyne]

There may be something I'm missing here, but here's the scenario:

• Play Mario 64 using lr-mupen64plus
• Go to the top of the first level, pan the camera so you can see the entire level.

Now, rendering the entire level like that lags, of course. But, when checking the clock speeds of the cores, the v3d core is always 0 when that happens, otherwise it is as 550 as it should be. The core seems to be 'turning off' when too much is thrown at it.

I'd like to know if that is a bug, normal behavior, or if it is happening due to something else?

More information

320gb of vram. 51.5C is the highest temp I've seen it at so far.
I am currently overclocked, but the lag in the same places happened I OC'd as well. I'm using RetroPie 4.2, and it was installed on top of an existing raspbian install. (I've seen similar behavior on a friends rpi though, and it was installed from the RetroPie image).

pi@host:~ $ for src in arm core h264 isp v3d; do echo -e "$src:\t$(vcgencmd measure_clock $src)"; done
arm:    frequency(45)=1400000000
core:   frequency(1)=550000000
h264:   frequency(28)=550000000
isp:    frequency(42)=550000000
v3d:    frequency(43)=550000000
pi@host:~ $ for src in arm core h264 isp v3d; do echo -e "$src:\t$(vcgencmd measure_clock $src)"; done
arm:    frequency(45)=1399998000
core:   frequency(1)=549999000
h264:   frequency(28)=550000000
isp:    frequency(42)=550000000
v3d:    frequency(43)=0

Any help or insight would be greatly appreciated.