
It is difficult to find conclusive information, especially since Nostalrius' combat mechanics may actually be different to retail vanilla. This may not be entirely accurate - see this discussion on Elitist Jerks (. This is largely based on information from The Dalaran Tome of Knowledge (see ). It is also assumed that for every 10 frost resistance the enemy has, your damage drops by 2.5%.
You have 3/3 Piercing ice, increasing the damage done by frost spells by 6%. You have 5/5 Ice Shards, making your crits deal 200% damage. You have 2/2 Arcane subtlety, giving you a base of 10 spell pen. You are using rank 10 frostbolt and nothing else. You are fighting a level 63 enemy (a boss). Then, put the stats for the item in the "Item Comparison" section and the spreadsheet will calculate which is better. If you want to compare two items in a certain slot, set your stats to be as they would be without any item in that slot. You will see that stat weightings based on your gear are calculated, as is your expected frostbolt damage and DPS. Put in the stats box your current gear (for reference, example stats for certain sets of gear are given at the bottom of the spreadsheet). Make a copy of the spreadsheet in your Google Drive so that you can edit it. Work out how much a particular piece of gear improves your damage, allowing gear to be compared. Calculate stat weightings for spell power, intellect, crit, hit, and spell pen. Calculate your expected DPS with frostbolt. Calculate the average damage of your frostbolt with your current gear. If you don't want to read the rest of this post, just look at this spreadsheet: Crit and hit in particular become more valuable the more spellpower you have. Stat weightings are not constant values, but rather vary according to the actual stats you have. This is important because it allows us to accurately compare two pieces of gear to work out which is better.
This post is for those who are interested in calculating the theoretical average damage of their frostbolts, and also finding out exact stat weightings for frost mages.