Conan, as many, even most 2d20 games, offer the players a lot of choices on using skills, Talents, Momentum spends, whether to generate Doom/Threat/⌠or to spend Fortune/Infinity Points/⌠etc.
For some players those decisions will take time - a long time for some. And that is, in my experience, for some players who now play 2d20 games since MC3 (so for several years) still the case. They simply cannot make their mind up - especially with Momentum spends after the roll. (There is the penalty for wasting time in the GM adding Doom after a while, but that punishes the whole group, so I tend to use that only if the whole group is talking themselves into circles without getting anywhere.)
Most players, though, get around that and know their most often used Momentum spends, their Talents and when and how to use them, quite well, so the task resolution, especially, but not only, in combat scenes gets quicker - though not really quick.
(Really quick is more the case in Dishonored or Dune, where conflicts are resolved on a much more abstract level, so you donât have to bother with all those details that Conan or even more so Infinity and MC3 offer.)
Higher competent characters tend to shorten combat scene significantly, too. And in the hands of an experienced 2d20 player, things âclear upâ in a very short time. - I often have combat scenes that take two rounds to fully resolve, unless I deliberately design the zones and the opposition to make them last longer - for a boss fight kind of scene, for example.
Another time consuming part is the initiative. In other games you determine the initiative, serialize the turns for everyone and youâre good to go over the whole combat. In Conan your PCs will have ALL their turns before the NPCs might act. That means, the players have to decide which one of them takes the turn, who comes after that, etc. - and without any mechanics to support that decision making. And, as in the case above, some players or even some groups are very slow on coming up with any kind of decision - and that can slow down Conan combat scenes very significantly.
It is a meta-gaming part, even a player-empowering part, but still it could, depending on the players, eat up a lot of time. - And running a game for a 5 or 6 PC group, where half a dozen people need to decide how to serialize their turns, well, that makes for some waiting time.
If the GM interrupts by spending Doom, that could wreak havoc on the tender sprout of agreed upon sequence of turns the players finally decided to take. So if the first PC took the turn, the GM interrupts, takes the NPCâs turn, then the rest of the PCs can act, the newly created facts of the NPCâs actions might prompt another round of negotiating the sequence of PC turns.
Some groups get that resolved - which often depends on the force of personality of a player who takes the role of coordinator of the player group. If you donât have one of those, things get slowed down at the start of every round with some groups.
In general, Conan 2d20 is a âmid-levelâ complexity rules set, so resolving tasks will take less time with experience by GM and players, but there is a certain point where you cannot speed things up anymore. To reach that, you need players (and GMs) who think in advance to plan their moves, who very quickly decide who gets to take their turn in combat, who know their charactersâ abilities and the general rules, options, different types of actions and when to take them.
Then there are GMâs decisions that could prolong especially combat scenes to take out all the momentum (lower case, not the resource Momentum).
If the GM for example musters up too many Toughened opponents, especially with sword and shield, so they get to perform Reactions without spending Doom right away, then the opposed rolls can eat up time like nothing. Add to that the Cover Soak from shields and some decent armor, and your Toughened NPCs last longer, have to be whittled down - except by the combat monster axe-wielder (Intense weapons = Toughened one-hit slayer, and even Nemesis one-two-hit slayer).
As a GM you need to get the feeling when to cut a scene, when to move things forward. There is no hard and fast rule for that - and I often enough tend to let things play out beyond their time of welcome, too.
In combat scenes, you can shorten things after a while by letting the opposition surrender, flee or simply not use any Reaction (even if it were a free one), to get things moving forward.
There is a lot more to say about pacing in Conan in general - and how to use Doom for that.