I also use an Enermax EG651P-VE and my +5V rail is actually around +5.10V with almost no load.
I plan to apply this mod to my Enermax if the +5V rail should go under 5V at full load (all 4 HDD's, fans, CD, CDR, DVD, CCFL's connected):
http://members.rogers.com/2caaronc/Enermax%20Mod.htm
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