Just curious since its a huge boost in a secondary stat.

Depends on the class.
icy veins has whieghted values for each stat for some classes.
From there it's some simple math to compare the overall value of stats on a lower ilvl with socket to higher without.
I'm gonna guess that in no situation does the socket win unless your comparing lower ilvl with ideal secondary stats to higher without the ideal ones.

Certain pieces with a low stat count, like bracers and cloaks for example, have a higher discrepancy.

It also depends on how strong a particular secondary stat is for your class.

You'd have to simcraft the piece to have a totally accurate answer.

But a lower ilvl piece can easily be an upgrade with a socket. Even without your two best stats on it.

I agree with the above it just depends, but sockets can be very valuable. Unfortunately I don't know the answer to the question you posed.

But I kept a trinket for a while that was only ilvl855 because it had a socket and with a gem it had more crit than one 10 ilvls higher.