You will need frost resist gear for Sapphiron

[Kynes]

I've MT'd all our Sapph kills (10 and 25) and never used an ounce of FrR. The only people in our raids who DO are dps, just to give the healers some leeway.

But yeah, on our first attempt for 25 man, we 1 shot Sapph. The FrR for dps makes a huge difference.

[towelliee]

We killed Saph with no FR the last 2 weeks. Simple and an easy raid achievement. I can't believe I actually spent the money on the 3 piece FR hopefully it can be useful in Icecrown in the future.

[antiy4ho0]

Sapphiron has stopped us 2 weeks in a row. The first week it was late, and it was on our second night. So it was expected. This week...not so much. Our best attempt was to the 30% ish range, but nothing after that got close. We're running with 3 healers, no resist aside from 130 from totem/aura. 2 Resto Shammy 1 Resto Druid. One of our resto shaman is amazing, hes my healbot for my heroics and has healed me through pretty much all achievements and things that I should of died from. The other resto shaman is pretty good as well. Our resto druid is a recent respec from balance and needs work managing mana for longer fights (such as this...) but with a mana tide in the group she can get through it. The problem is...just that everyone constantly need heals. Sapphiron doesn't hit like a truck to where constant big heals are needed, but he hits pretty hard. Heals are just stretched, and next week DPS are expected to be carrying frost resist in their bags.

[Samilyn]

It's definitely doable without resist gear. We got the achievement on [10] using only holy priest/resto shaman/JoL for heals and the entire raid had exactly 0 resists.

The aura damage is extremely predictable, and as such your group healers should have VERY little over-healing. There's no point in topping everyone off so that they can survive the next tick of frost aura.. until flight phase which has raid burst damage.