This build is really overpowered at PvE and there is no many pure melee PvP builds what would stand against this insane killer build.
The Primal Rager is not intended as a good example for power gamers. It is merely a simple, straightforward damage build, which can be used as reference for real power builds. This way you know, if all the effort you put into creating your new character is able to overpower a build which requires absolutely no skill to realize.
Race: Earth Genasi
Why these classes/races?
Earth Genasi gives STR+2, which is mandatory since you need STR 30 for Epic Rage. Half-orc or Wood Elf works as well. In more sophisticated Epic-Rage builds, variations with 2 or 4 Red Dragon Disciple levels may open up other races as well. For the purpose of this build the advantages of the different races are, however, irrelevant.
At CL 30, the Rager has a natural strength of 30. Epic Rage gives a +10 boost to both STR and CON. Greater Frenzy gives a +10 boost to STR. Since Frenzy and Rage stack, the end result should be STR 50.(This is not true, as you only gain a maximum of +12 to STR, as every attribute increasing skills and items have a total cap of 12) You also end up with 660 hit points, which make up a bit for your miserable AC.
That is not the case. Instead you get a meager STR 42 boost, which is probably a bug: Attribute boni by items are capped at +12 and apparently the same applies to feats.
However, let's see the battle performance numbers:
(All examples except the last ones are done without any magical equipment, wielding a Great Sword.)
When calm, the Rager shows off these values:
Main Hand Attack Bonus: +42/+37/+32/+27/+22/+17 Damage: 2-12 + 15
When raging and frenzying (STR 42):
Main Hand Attack Bonus: +48/+48/+43/+38/+33/+28/+23 Damage: 2-12 + 24 Frenzy adds an extra attack at the highest attack bonus. This doesn't show up in the character sheet)
When raging and frenzying (STR 42) and using Supreme Power Attack:
Main Hand Attack Bonus: +42/+42/+37/+32/+27/+22/+17 Damage: 2-12+48
Assuming, every attack hits, you're looking at an average per round damage of: 7 * (7 + 48) = 385
The equation changes a bit if you wield endgame equipment: Greatsword+8 +5d6 fire +5d6 cold +5d6 electric. (no STR items, because STR bonus is capped at +12).
Endgame equipment when raging and frenzying (STR 42) and using Supreme Power Attack:
Main Hand Attack Bonus: +50/+50/+45/+40/+35/+30/+25 Damage: 7 * (7 + 48 + 8 + 3 * 17.5) = 808.5
Now imagine, that rage and frenzy DO stack, giving you godly STR 50.
Endgame equipment when raging and frenzying (STR 50) and using Supreme Power Attack:
Main Hand Attack Bonus: +54/+54/+49/+44/+39/+34/+29 Damage: 7 * (7 + 54 + 8 + 3 * 17.5) = 850.5
This doesn't include criticals or other buffs. Also keep in mind, that in case the rager kills something, the next victim gets two free friendly slaps, due to Supreme Cleave. And, since we also have Great Cleave, you can apply those double freebies unlimited times per round. If you happen to kill two creatures in a round, your damage output can reach 1300 points of pain. Not likely, but possible.