I profiled both and got a hit on the following instruction in Adobe AIR.dll:
sub rsp, 0x28
Took 55.3% of the test time @ 32 seconds!
This one at 16.1% @ 9.3 seconds.
Both in the 64 bit version.
In the 32 bit version:
23% @ 5.5s
5% @ 1.2 seconds
No idea what that assembly means without looking but that "sub rsp" stands out!