For a long time, the go-to quintessences for magic damage champions have been flat ability power. If not flat AP, people generally run movement speed or some kind of survivability (MR, Armor, flat HP) in their quintessence slot. There is at least one other option though—magic penetration quintessences. While prevailing wisdom is that 6 magic penetration does less damage than 15 AP for most spells, that prevailing wisdom was derived in 2012 before the penetration changes and was created for a general case. In this blog post, I, Sudunem, will explore in-depth the specifics of how magic penetration quints compare to flat AP.

The Comparison

3 flat magic penetration quintessences give an additional 6 magic penetration. 3 flat AP quintessences give 16 ability power when you factor in the Archmage mastery (5% AP boost). I’m going to assume that you’re also bringing 9 flat magic penetration marks (8 magic penetration) and the 8% penetration mastery (Arcane Knowledge), as well as 6 flat ability power from Mental Force. To compare these properly, I will look at 4 different levels of magic resist for the target.

Minions have effectively 0 MR until at least the 30 minute mark due to magic penetration marks.

Champions start with base 30 MR

Champions with 9 flat magic resist glyphs have 43 MR

Champions who either buy a fast Null Magic Mantle on top of their MR glyphs or who are melee and receive MR/level along with defensive masteries will obtain approximately 70 MR by level 13. This could also approximate a Runic Bulwark aura on a 43 MR target.

Runes are more of an early-game choice, so I will talk more in depth about the level 1-6 options, but also mention the lategame implications.

Graphs

Each one of these charts is a comparison that varies the base damage (vertical axis) and AP ratio (horizontal axis). I then subtract the damage for the magic penetration case from the ability power case, so that a negative number means that magic penetration does more damage, while a positive number indicates that ability power quints inflict more damage. To aid in reading the charts, the cases where magic penetration yields more damage are in blue while the cases where ability power yields more damage are in red.

0 Magic Resist case

I’m not going to insult your intelligence with a graph for this one. Obviously, flat ability power is better against minions in every single case.

30 Magic Resist case

With a quickly rushed Sorcerer’s Boots or Haunting Guise: With an innate 15% shred or reduction (Karthus, Xerath’s Rank 1 Locus of Power). While the process for calculating shred versus penetration is different, in this case, it doesn’t make a substantial difference, so we can treat them as approximately the same.

43 Magic Resist case

With a quickly rushed Sorcerer’s Boots or Haunting Guise:

With an innate 15% shred or reduction.

70 MR case

With a quickly rushed Sorcerer’s Boots or Haunting Guise:

With an innate 15% shred or reduction.

Lategame For kicks, let’s see what happens in a lategame scenario, theoretically around the 30 minute mark when the core builds are about done and solo laners have access to their rank 3 ultimate. The target has 70 MR while the caster has Sorcerer’s Shoes or Haunting Guise/Liandry’s Torment, along with 250 base ability power (before the quintessences are added).

Results

That was a lot of tables, but what does it all mean? First, at level 1, ability power is the better choice. You would need a spell that does over 150 magic damage at level 1 with a low AP ratio. Beyond certain DoTs (Poison Trail), those don’t exist. For that same reason, at level 3, flat ability power is usually the better choice. Almost every basic magic damage spell at rank 1 has less than 100 damage, and if it has a higher damage (Anivia, Veigar), it comes with such a high AP ratio that ability power is a better choice. The exceptions to this are usually %health nukes that don’t scale well off AP. At level 6, AP tends to remain the better choice, even on mages with high base damage values (i.e. Lux), but the gap narrows. At level 9, there a number of champions with high base damage values on their main nuke who could benefit more from magic penetration than they would ability power. For example, Kassadin’s Null Sphere has a high base damage (280) and a moderate AP ratio (0.7). Against a 43 MR target, Kassadin will squeeze out about 2 more damage per Null Sphere and likewise with Force Pulse once he maxes it at level 13. However, Kassadin’s Rift Walk has a low base damage and higher AP ratio unless he stacks it heavily. The choice for Kassadin to opt for magic penetration versus ability power would depend on which spell he prioritizes using offensively. If he’s only using Rift Walk once to close on the target, then AP is better at rank 1 Rift Walk. With each extra Rift Walk stack he adds over two, he will make the Q/E/R trade favor magic penetration more, particularly with more ranks in E. Rumble’s Equalizer also benefits more from magic penetration than ability power at all ranks against targets with 70 MR or lower. Lategame, magic penetration is the better choice for most mages, so if your champion can afford to play defensively until 30 minutes and doesn’t need the ability power to snowball the midgame between 15 and 30 minutes, magic penetration would be a good choice. For example, Veigar has incredible AP ratios, but he also benefits from magic penetration more in the lategame and would definitely prefer to farm up for 30 minutes. By the way, in case you were wondering, mixing the AP and MP quints does not yield an appreciable change against a 43 MR target—if anything, mixing them just tends to favor AP more.

Champion choices

I’m not going to evaluate every single magic-damage champion in-depth to see which choice would be “better” on them. That would be very tedious, and the answers will depend on the champion’s playstyle and other factors beyond just “maximum damage to champions.” Plus, Riot is prone to changing AP ratios and base damages all the time, so the charts above, pending any changes to magic penetration or ability power runes, should suffice for your needs. Instead, I’ll give you some guidelines that either encourage or discourage magic penetration quintessences.

Discourage The following traits discourage the use of flat magic penetration quintessences.

The champion has an AP-scaling shield or heal, such as Orianna, Nidalee, Diana, Galio, Sion, or Morgana.

The champion’s primary nuke(s) have a base damage of under 250 with an AP ratio greater than 0.6. For example, Lissandra or Diana. If your champion is hitting 0.8 or higher on their main nuke, bring more AP. Examples of this are Akali, Sion, Malzahar, Swain, and Anivia.

The champion gets some additional statistic from ability power, e.g. Vladimir or Akali.

The champion uses their ability power to farm and does not need to snowball their lane. This is a long list, but includes Morgana, Twisted Fate, Karthus, Galio, Anivia, Lux, Orianna, etc. If the champion needs certain amounts of AP at an early level to farm, stick with AP quintessences.

The champion really needs movement speed quintessences. Ryze comes to mind here—otherwise, magic penetration quintessences would be great on him. Seriously, don’t run AP quints on Ryze.

The champion has high level 1-6 kill potential and reasonable ratios. Unless your damage doesn’t scale with AP at all, AP quints give more damage. Fizz is the poster child for this category.

Encourage The following traits encourage the use of magic penetration quintessences

The champion has %health damage, particularly %health damage that scales extremely poorly with ability power. Elise, Mordekaiser, Brand and Dr. Mundo are prime examples of this.

The champion benefits heavily from early magic penetration such as Haunting Guise or Sorcerer’s Shoes, and/or really likes Liandry’s Torment. Elise once again exemplifies this.

The champion does not use their ability power to farm in the midgame. E.g. Heimerdinger, to an extent Kassadin.

The champion can’t or shouldn’t pressure the enemy before level 6, such as Kassadin.

The champion has very low AP ratios, or has a spell that doesn’t scale off ability power. Dominion players will hate me for this, but Heimerdinger’s turrets use his magic penetration, but not his ability power, and his rockets are a prime example of a high base damage (285 at max rank) and low AP ratio (0.55) nuke.

The champion wants to play for lategame and abuse either %health damage or a very high base damage ultimate. Rumble, for example, does more damage with magic penetration than ability power on a rank 3 Equalizer (about 6 damage per tick, or 32 more damage total). Lux is another example of this—with a passive proc, she does 18 more damage per laser lategame on a 70 MR target with magic penetration quintessences.

Conclusion

The prevailing wisdom holds out, by and large, for most AP champions when it comes to quintessences. Before level 9, ability power is almost universally better than magic penetration unless you are Dr. Mundo or Elise. Ability power also helps with farming and powers shields and heals, so if your champion is focused on pre-level 9 play, shielding, or healing, or passive farming, run ability power quintessences. Some champions gain a bit more damage out of magic penetration at rank 9. Features that make magic penetration better include very high base damages, %health damage, early magic penetration rushes, and low/non-existent AP ratios. Also, many mage ultimate spells do more damage when fully ranked with magic penetration than ability power. Lategame, the choice swings the other way and magic penetration provides more damage. Since your situation, playstyle, and champion will all vary, I hope to leave you not with a series of absolutes that dictate THIS IS BETTER ON THIS CHAMPION, but rather awareness that magic penetration quintessences can be a valid choice, particularly for the lategame, or for champions with very low AP ratios and/or %health damage. It’ll be up to you to decide whether that tradeoff is worth it.

Thanks for reading and a special thanks to SS for your assistance with this analysis. Please consider liking the Cloth5 Facebook page or following our Twitter.

.