Quote from nuhertz
I believe MP4 and MP5 are the most efficient Monster Power levels to loot items. The math seems straight forward, and my unscientific in game play seems to confirm.
I'd love to hear thoughts on if you think this is correct or not.
You do the same amount of damage in all MP levels.
You can handle the incoming damage in all MP levels.
Length of runs are directly correlated to Monster Health.
I think MP4 or MP5 is the sweet spot.
When you take the increase in health, and divide it by the bonuses you get with each MP, MP4 and MP5 get roughly the best bonuses. After that, the health of the monsters scales up far more than the additional bonuses.
I'd bet with a large sample size and the best characters you'd see the best returns on MP4 or MP5.
With budget characters that die on MP4 and MP5, it obviously will not be the same story.
The ratios in the link below show what the cost is in health for each % of the given stat. So for MP1, for every 15% health bonus given to monsters, you get 1% more XP. It drops to 10% health/xp around MP4-5, and then starts going back up. Same story for MF/GF and bonus items.
Thats fine and dandy, but you dont factor in anything else that affects MF and gold find. Add 75 to MF,GF and XP bonuses and see how that changes the ratios. Add a star ruby (+25% experience) to those ratios. Add whatever MF your paragon is with MF from your gear and your follower. As those numbers go up, the bonuses from higher MP have less of an effect. Note: All +% bonuses are added together first, so a 10% gain and a 10% gain from a mob that would normally give you 100 xp, gives you 120 exp (100 * 1.2), not 121 (100 * 1.1 * 1.1)
For example, going from 200% XP with 5stack valor and a star ruby, to 210% xp (with MP1) is only a 5% gain from what you would've had without the MP bonus.
As shadow bane stated, each successive MP gives less of a reward bonus factoring in 5stack, and that gets further diminished with any +EXP/GF/MF your character brings to the table. The only time it really makes sense from an efficiency side is if your DPS overpowers the health of the mob, so there is negligible clear time difference from raising the MP.