Firefox 64 vs 32 bit memory consumption

I opened the same tabs in 32 and 64 versions of FF and the difference in memory consumption is staggering.

Is there anything I can do on my end to reduce the gap? Or is 3x difference to be expected?

FWIW

1. I limited FF processes to 1 and disabled HW acceleration in both versions.


2. Yes, I already bought more RAM. Yes, I can live with this.