The T4400 has the following advantages over T5750
-as higher clocked than the T5750 by 200 MHz
-has a system bus of 800 MHz over the 667 MHz of T5750
-built under the 45nm technology and is smaller die size than the T5750
-410 million transistors over 291million in T5750
while T5750 has 2 MB cache advantage over 1 MB cache in T4400.
i would recommend you a T4400 over T5750 because i don't think 2Mb cache of T5750 with lower clocks would be better when you consider the faster bus and clocks of T4400 with a 1Mb cache.