Thought I would do so testing on the PTR to see what the HP scaling was like for Ghom and Diablo along with other bosses on Inferno to be added at a later date. I also took the amount from Live (1.0.4) for an easier Reference. Feel Free to add more Bosses to this thread.
Please Note this was based on one player! and you should add 70% to the totals for each additional player that joins the game (Max 210% for a full party)
People have been asking me about this and wasn't sure the best way to look into it, I didn't even think of bosses... Probably because I don't know if I'd survive long enough to get to many of them on MP10 hehe.
I'd be interested to see what you come up with, I might do some tests on normal monsters and if/when I do, I'd be happy to come back here with the data.
I ran some of the numbers in Excel just to see with your data. Looks like the increase is very easy to predict with these boss numbers, they equaled out perfectly.
The formulas were pretty simple, but someone should double check I got this right as it's been awhile since I worked with percentages. It looks like the HP increase goes down a little bit per MP but then jumps up a massive amount at MP10. 75% increase in HP values from MP9 to MP10. That's impressive.
Increase from base (MP0) to MP10 is =(MP10 HP / MP0 HP) - 1
Increase from MP9 to MP10 is =(MP10 HP / MP9 HP)- 1
So what kind of stats are people seeing success on in MP10 for all the classes?
I went in to try it out with 80k dps and 6% Life steal. I knew I couldn't do it but I did figure out that I have no problems clearing power level 6-7.
The impression that I had doing MP10 is that it is for a party of 4 that is geared. Do monsters gain more HP when you have a group?
The way it works as above, is that it adds another 70% to the base figure for every player that joins the game so in theory at MP10 Diablo on Inferno would have 257,601,872 HP Plus 70% Times 3 (210%) which would = 798,565,803 HP if I have done the maths right.
Based on your added Leoric numbers, I estimate his MP 10 HP value to be 193,196,863.
His data is very unique and shows us what happens to Act 1 monsters, proving the jump to mlvl 63. His HP eclipses Ghom even though he's in an earlier act. (UPDATE: My raw HP graph appears off, think I used the wrong settingFIXED)
As you can see from the graphs, the increase from Base HP is HUGE becuase of the jump from level 61 to level 63 combined with the Monster Power HP increase. While the numbers are larger, the curve is the same and the jump in HP per monster level (aside from the initial jump at MP1) are all the same. I'd like to say we have our verified increase for act 3/4 Q.E.D. would just like to see more data from act 1 and some from act 2 to see if the jump to MP1 is the same value.
lol SK has more HP than Azmodan
i really hope someone reported that to Blizzard and they fix this mess
While Azmodan is pretty low on the difficulty meter, once he starts making pools you have to run around quite a bit more than you ever really have to on SK. You also have to dodge the fireballs and lazors, whereas SK only the windup swing presents any real threat. A lot more DPS time = shorter/easier fight even with higher HP.
Just added Siegebreaker to the list and to my surprise his HP scales exactly the same as Azmodan from Live (1.0.4) to MP0 - MP10 as where Ghom only did this from MP0 - MP4.
Interesting data. Looks like we won't get the information from the bosses that I thought we would. It seems their HP values have been set in a very deliberate manner. As you mentioned Azmodan and Siegebreaker are identical and Leoric not only passes Ghom in HP, he has an odd relationship with the Butcher. Leoric has more HP than the Butcher on all MP except for 7, 8, and 9.
A look at the next chart gives us a good glimpse at the comparisons now. Every Boss has a companion that was boosted the same amount in MP10. The most boosted monsters are the easiest, being the Butcher and Leoric. They are followed by a distant second by Maghda and Zoltun Kulle.
This last chart I think seems to be the most interesting. It looks like each boss's overall difficulty curve is set when the boss is put on MP1 and then is given a fairly linear HP boost per point of MP. Most bosses seem to get something along the lines of 40% HP gain per MP level up to MP10.
The exceptions here are Leoric, Ghom, and Diablo who all get a fairly sharp HP increase at MP10. Zoltun Kulle is the odd man out as most of his HP levels are uneven and seem to be very specifically set up.
Unfortunately it looks like this data isn't going to help us too much in determining normal monster HP gains. That's going to take some time due to the range of HP values that monsters can have...