Perserved Contaminant Ranking Guide

Preserved Contaminants can be purchased from MOTHER in the Chamber of Heart. They allow you to apply a specific corruption effect to one of your items. This is a cool way to get that one effect you are missing, and it raises two optimization questions that we have tools to help you with.

1. Which contaminant should I buy?

The first question is fairly easy to answer. You can use our Corruption Effects Upgrade Finder search to see a ranked list of effects. Make sure to examine both ranking method options – probably the most useful is the “per 20 corruption” ranking option. In general you want to get the most out of each point of corruption on your gear.

2. Which item should I put it on?

We have added a Preserved Contaminant Upgrade Finder search to help you with this. You choose the contaminant you want to apply, and then we will suggest which (if any) item in your inventory you should modify, and show you how much of an upgrade it would be over your current gear.

How do we do the ranking?

Preserved contaminants was a tough one… the number of combinations gets pretty insane, and there are a lot of potential ways that a person could think about this problem. We ultimately chose one of the more straightforward approaches:

  1. We create a modified version of every item in your inventory that can be corrupted that has the contaminant applied to it, and add it to your inventory.
  2. We run a special Best in Bags optimization that ensures only one item with that contaminant can be chosen.
  3. If the result increases your score and contains an item that used the contaminant, we show you the score increase and which item it chose to put it on.

We think that this will be helpful to most people as a suggestion or guideline, even if it is not an “exhaustive” way to handle this optimization problem.

Notes and Options

  • The only main option is that you can specify items you would never want to cleanse to apply this new corruption effect from the contaminant. This is useful if e.g. you have a corrupted item that is situational but doesn’t score that high, and you want to keep it around.
  • We only consider adding one of the specified contaminant to your gear. They are relatively expensive, so this shouldn’t be a huge limitation for most users.

Implementation Discussion

There are a lot of other ways that we could have approached this complex optimization problem. One that we explored first was a sort of “corrupted BiS” option. Given a desired amount of corruption, list out the top 10 or 20 combos of corruption effects that I could possibly get. Then people could use that as a guideline to choose a contaminant.

We quickly had to toss that idea out the window… the number of combinations is far too large. For example, if you have 60 corruption resistance (50 from cloak, 10 from an essence) and want to keep your total corruption at 59 or less (to avoid triggering that nasty 60-corruption penalty), that gives you 119 corruption to spread across your gear. Take an unholy DK as an example, they have 8 slots that can have corrupted gear, and some effects you can skip, like siphoner. After pruning to just effects that have some value and can be used by unholy DKs, there are 11 million relevant corruption combos.

Pile on top of this the further complication that e.g. the crit corruption effect Severe (multiplies crit gains from gear) has a highly variable value depending on your other gear/stats… you have a very large solution space to explore.

Thus, we decided to back off and go with the current approach, which gives a more “temporary” answer, but is probably more immediately useful to players. It is “temporary” in that the solution depends on the specific state of your gear right now. It’s not a tool for planning ahead to some BiS combo of corruption effects a few months from now.

But we think that it being more “immediately useful” balances that – if you have the currency to buy a contaminant right now, it gives a pretty solid recommendation of what to do.

This latter perspective is more in line with our overall gear philosophy as well: trying to plan way into the future chasing some “BiS” collection of gear isn’t a great way to play WoW anymore. The gear you get each week is random, how much gear you get is random, etc. It is better to take a “greedy” approach to gearing: what is the best thing that I can do right at this moment based on my current gear? Do it, enjoy for however long it lasts, repeat.