After reading through the threads in the tome about Conserve MP, my general impression was that we still did not have enough information about this trait to understand how it really works. So I have decided to do some testing and compile the results here.
My goals are to determine a baseline profile for Conserve MP activation (how often, how much) and to determine how the "Conserve MP +X" stat on various equipment alters this profile. I am only interested in drawing statistically sound conclusions.
Like some of the previous studies on this trait, I cast the same spell many times. I chose to use Cure III for the first batch. The intent was to provide sufficient resolution (costs enough MP) to verify that activation is in n/16 amounts (previously asserted by others who have studied this) and be able to recast quickly (I don't have all day to sit around casting on myself). I did the casting on various days (excluding light and dark days) and various moon phases. I faced north for all casts (I may repeat facing Northeast). I did 500 casts while wearing no body armor. I did 500 additional casts while wearing my Igqira Weskit (Conserve MP +2). Other equipment was kept the same. I was level 73-74 BLM/WHM while doing this.
Update: Added another data set as 75BLM wearing Igqira Weskit and Water Ring (conserve MP +15 on Watersday) for a total of Conserve MP +17. All casts were performed on Watersday, of course. Also added adjusted percent saved calculation (see below).
Summary of the Results:
No Body Armor
Casts: Cost # % 46 375 75.0 43 19 3.8 40 13 2.6 37 25 5.0 34 17 3.4 31 13 2.6 28 17 3.4 25 8 1.6 23 13 2.6
Totals: Casts 500 Nominal MP 23000 Actual MP 21468 Pct. saved 6.66 Adj. pct. saved 6.44
Casts: Cost # % 46 394 78.8 43 12 2.4 40 11 2.2 37 13 2.6 34 11 2.2 31 10 2.0 28 14 2.8 25 20 4.0 23 15 3.0
Totals: Casts 500 Nominal MP 23000 Actual MP 21482 Pct. saved 6.60 Adj. pct. saved 6.39
Igqira Weskit + Water Ring
Casts: Cost # % 46 288 57.6 43 29 5.8 40 29 5.8 37 38 7.6 34 23 4.6 31 31 6.2 28 22 4.4 25 22 4.4 23 18 3.6
Totals: Casts 500 Nominal MP 23000 Actual MP 20384 Pct. saved 11.37 Adj. pct. saved 10.98
A statistical analysis of the numbers has not yet been done, but there is one thing that sticks out: The difference in actual MP saved between the weskit and nothing is very, very small. In fact, I spent 14 MP more wearing the weskit than I did without it. Yay.
Although I disagree with some of his analysis, if you look at SirJac's Post, these results are comparable with his.
Update: With the addition of the Water Ring, there is a definate increase in both the number of times that Conserve activates and the total MP saved. By casual inspection, it doesn't appear that there is a huge difference in the relative distribution among the various amounts of MP saved per cast.
It has also been noted that rounding down occurs when the spell cost is not a multiple of 16. This results in slightly inflated conserve percentages, the amount of which will vary in practice depending on the actual spell used. I have added an "adjusted" percentage which corrects for this rounding.
As expected, actual MP costs are represented as the integer part of n/16 * nominal cost, where 8 <= n <= 16.
Lv 73-74 BLM/WHM can expect around 6.6% baseline reduction in MP actually used over the long term.
If the bottom line difference is not statistically significant over the course of 500 casts, then it is fair to say that the Conserve MP +2 bonus on the weskit has no practical impact upon gameplay.
Update: It appears that the primary mechanism of the +Conserve MP stat is an increase to the frequency with which casting cost is reduced, rather than a change to the amount that is reduced with each cast.
It is entirely possible that there are variables that I have not sufficiently accounted for.
Repeat facing different directions.
Repeat using other spells.
Repeat using baseline equipment on one day only.
I will post updates here as I get them (more data, more detailed analysis, etc.).
Edited, Wed Feb 15 14:23:20 2006 by VxSote