[ruby-core:30855] requires in 1.9 are slower...

Hi all.
I've noticed that with 1.9.x, requires seem to take a bit more than
twice the time they did with 1.8.6

ex:

1.9.1:

C:\dev\ruby\faster_rubygems>ruby-prof C:\Ruby19\bin\whichr -- whichr | head -n20

 %self     total     self     wait    child    calls  name
 58.67      0.28     0.22     0.00     0.06       23  Kernel#require(d1)
 16.00      0.06     0.06     0.00     0.00        3  Kernel#require(d2)

1.8.6:

C:\dev\ruby\faster_rubygems>ruby-prof
c:\installs\ruby-1.8.6-p388-i386-mingw32\bin\whichr -- whichr

 %self     total     self     wait    child    calls  name
 60.00      0.10     0.09     0.00     0.01       23  Kernel#require(d1)
 13.33      0.02     0.02     0.00     0.00      322  <Class::Dir>#glob
  6.67      0.01     0.01     0.00     0.00      644  Array#select

(same 23 calls, but they take a bit over twice the time).
Just pointing it out.  Any ideas as to why?
Thanks.
-r