Yep, speed 100-110s. After that, it’s just about logging enough hours. If you are playing efficiently, it honestly doesn’t take that many though, even as a solo player. A few hours a day over the entire season (this could include some 8 hour days on weekends and some weekdays you don’t play at all) should do it.
I got to 2000 paragon this season in about 250 hours (about 3 hours a day), mostly doing speed 100s on Vyr’s and speed 90-100s on UE. Largely solo (I did a tiny bit of zmonk for a friend who wanted to push 2s, but that wasn’t very often and the vast majority of my XP was earned solo). Oh, and I guess 4000 bounties worth of pub bounties.
It’s generally more XP efficient to do something like 105s or 110s as HunterKiller mentioned. You can see he got to 2000 paragon significantly faster than I did.
It also depends a bit on the speed you run them in, it’s a sliding window. Optimal GR tier for speeds might change a bit with the new DH set (it looks like it might do a bit higher a bit faster). But as a rough idea, generally 2-3 min rifts give a little more gem upgrades/hour, legendary drops/hour, and shards/hour, at the cost of a little less XP/hour, and more keys burned (so you have to spend more time running T16 rifts). 3-5 minute rifts give a little more XP/hour and fewer keys burned (this translates to less time running T16 and more time running GRs, which also bumps up your overall XP efficiency a bit), at the cost of a little less gem upgrades/hour, legendary drops/hour, and shards/hour.
That’s generally only efficient at higher paragon. At low paragon, you’ll generally earn more XP/hour just straight running GRs without pools instead of farming pools. There’s a point (in terms of paragon, more paragon means your pools last longer and are therefore worth more effective XP per pool) where it starts to become more efficient, or at least not a loss of efficiency, to pool up, but as power creep continues, that point gets higher and higher. Pools generally aren’t worth much at lower paragon. Spending the time farming GRs without pools instead of spending the time to farm up a set of pools will often net you more total XP per time spent.
Below 1500 paragon, I’d largely ignore pools. Not totally ignore I guess, if you’re doing T16s and you cap out your pools, you should switch to GRs to burn your pools quickly before you go back to T16s so that you aren’t wasting any excess pools you find. But if you always pool up to full then run GRs until you are out then pool up again, you’ll end up spending WAY too much time outside GRs (and you’ll have a massive stack of GR keys), which is not XP efficient. A full stack of pools at 1500 paragon only lasts 6 GR100s and 4.5 GR105s. If you are aiming to farm XP as efficiently as possible, you want a far higher ratio of GRs to T16 rifts than that. Even at 2000 paragon, a full stack of pools only lasts 9 GR100s and 7 GR105s.
