[popcornmix]

disable_pvt=1

Any reason for adding this?
The sdram spec says that sdram refresh needs to be done at a certain rate, and this depends on temperature.
PVT measures the chip temperature periodically (every 2 seconds I think) and adjusts the sdram refresh.

If you disable PVT, then a fixed, more pessamistic refresh is used, so it could hurt performance.

I think the overhead of a high refresh vs a low refresh is about 2%, so probably not noticeable, but I'm interested to know why it was added.