i was looking at the Space Marine Character sheet and saw that one of their augments under the power armour picture says that they get +20 strength. is that added to the starting strength or is that already in the starting strength.

thx

The +20 Strength is only there when wearing their power armour and it's added on after the Unnatural Strength bonus.

Pretty much every bonus goes after the bonus's for Unnatural characteristics.

So how does that stack to melee damage?

Example we have a Strength 41 Marine (base stat) with unnatural strength. So does this mean that with the armour they are 61 strength and for melee damage wise they add 12 damage instead of 8 Damage? Like wise for strength tests?

Deepstriker said:

The bonus to damage from Strength would be 10.

Unnatural Strength (x2) doubles the base Strength Bonus from 4 to 8. The +20 Strength boost from Power Armor then adds another 2 points to Strength Bonus. For the purposes of tests based on Strength, the character is considered to have a Strength score of 61 (41 base + 20 Power Armor). Depending on the test, he will likely also gain some benefit from his Unnatural Strength as detailed under the Unnatural Characteristic Trait.

A question along the same line. Marine bob has 50 strength SBx2 = 10. With his powerfist it gets pushed to SBx3 = 15.

OK, now in his power armour with +20 strength and the powerfist would his effective SB be 50 SBx3 = 15 + 20 SBx2 = 4 for a total SB19, or would it be 50 SBx3 = 15 + 20 SB = 2 for a total of SB17?

Logically, I would think the modifier from the powerfist would effect the added strength from the power armour as well, but I am not totally sure and it's something my gm friend and I are sort of up in the air about.

Thanks

Since in the description of the power fist it says it increases the multiplier they already get, that's 'all' it does (which is plenty.) So in the example you gave it would be the 17. get your strength to 60+ and have 2d10+20 pen 9... plenty good, and crazy when you use your strength boost..