Talk:Kassadin/@comment-4114531-20110716032454/@comment-4158654-20110717225748

CDR on Kass is awesome, don't get me wrong. It's just that with how mana hungry he is, you want to have blue buff whenever possible, which gives about 25% CDR at level 18. So if you get frozen heart, that alone is a waste of 5% CDR because of the 40% cap.

While a frozen heart does give great survivability, a Zhonyas gives 100 AP and a 2 second invincibilty active (with max CDR that's almost the entire cooldown of riftwalk!). And with enough AP, the enemy carries won't have the chance to make the extra armour/attack speed reduction from frozen heart useful because they'll be waiting to respawn. :D