So, I was mistaken. I didn't go from the 3200+ Winchester to the X2 4400+ in the file server.. It wasn't worth the hassle to find another 939 mobo just to keep on using the 3200+ after upgrading the CPU in my main rig. So, I stuck with the 2600+ until I changed platforms (and motherboards) in 2009.
Main rig:
Intel 200 MMX
Athlon 1200hz Thunderbird
Athlon XP 1600+ Palomino
Athlon XP 1800+ Thorougbred
Athlon XP 2200+ Thornton
Athlon XP 2400+ Thornton
Athlon XP 2600+ Barton
Athlon 64 3200+ Winchester
Athlon 64 X2 4400+ Toledo
Intel i7 920 Bloomfield
Intel i7 4790K Devil's Canyon
File server:
Athlon 2600+ Barton (from Main rig)
Athlon 64 X2 4400+ Toledo (from Main rig)
Intel Pentium G4400 Skylake-S
Intel i7 6700 Skylake-S