Originally Posted by
Schizoide
Blood Tap is off the GCD, FYI.
The DW T18N profile is GCD-capped, simming at 9% wait time. That profile has 1355 haste rating. For some reason it enchants one ring to haste too, which I assume is a mistake in the profile (not a big deal). Anyway, you get a ton more haste rating on gear plus high uptime on 5% haste from the set bonus (Obliteration sims at a whopping 78% uptime), and all that consumes GCDs.
The DW T17M profile, at only 775 haste rating, is also close to GCD-capped at 12.7% wait time. But not quite capped-- to me at least, 12.7% feels tremendously better than 9%.
There's not much point in talking about a cap, as you'll always want higher itemlvl gear and even when GCD-capped haste is DW frost's second-best secondary stat.