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So I tried using that set in OU and it has two pretty big problems: If it's not at +6, it doesn't threaten anything due to its base 50 Attack, and it has a really hard time setting up because of bad defensive typing. Things like Specs Keldeo are able to switch in and force it out. If you want to use Regice, I'd recommend a special set.
Or you could do this:
Regice @ Choice Specs
Ability: Clear Body
EVs: 248 HP / 252 SpA / 8 Spe
Modest Nature
IVs: 0 Atk
-Ice Beam
-Thunderbolt
-Focus Blast
-Hidden Power [Rock]
My favorite Regice set. You can just come in on most special attacks and kill things.