What's the actual damage for Fire Golem?

[Wyrm]

I've heard several different things mentioned, that it was always 100 Fire and 100 Phys, and another that it's his max HP amount. I've been working on a necro that uses this as his main attack (LR a pack of monsters and then keep summoning the golem over and over till they die, then waiting 10 minutes for my mana to regen and move on) and was wondering what the best way to allocate skills would be. I'm definitely maxing Lower Resist, but should I put points into Fire Golem or Summon Mastery as well?

[Obi2Kenobi]

I have a feeling that it isn't the life, since I have had one that had thousand of life points.