It's very likely zero or positive impact on the decompression side of things.
Starting with smaller data means everything ends up smaller. It's the same decompression algorithm in all cases, so it's not some special / unoptimized branch of code. It's yielding the same data in the end, so writes equal out plus or minus disk queue fullness and power cycles. It's _maybe_ better for RAM and CPU because more data fits in cache, so less memory is used and the compute is idle less often.
It's relatively easy to test decompression efficiency if you think CPU time is a good proxy for energy usage: go find something like React and test the decomp time of gzip -9 vs zopfli. Or even better, find something similar but much bigger so you can see the delta and it's not lost in rounding errors.
Starting with smaller data means everything ends up smaller. It's the same decompression algorithm in all cases, so it's not some special / unoptimized branch of code. It's yielding the same data in the end, so writes equal out plus or minus disk queue fullness and power cycles. It's _maybe_ better for RAM and CPU because more data fits in cache, so less memory is used and the compute is idle less often.
It's relatively easy to test decompression efficiency if you think CPU time is a good proxy for energy usage: go find something like React and test the decomp time of gzip -9 vs zopfli. Or even better, find something similar but much bigger so you can see the delta and it's not lost in rounding errors.