I did a wide variety of different runs / zone combos on my way to 100 -- at the end I was averaging between 70-80 mil xp/hr. From my experience, as much as it makes a good thread title and is good marketing, I wouldn't say Ogies run/zone selection would be 20-30% faster than an Alk run. I do agree Rakki's is a nice add that wasn't in Alk and I had that in my late Paragon levels 90-100. I also liked running Skycrown Battlements for a change of pace and put that in my runs on occasion as well.
I will say starting in Core/Tower of the Damned over many, many runs, there is just an inconsistent # of Elite packs. When things go well, and you pick up 2-3 in each zone, those are the highest xp runs I did. However, on an average basis, running Skycrown and getting a consistent 4-5 every time often suited me better. In the end, I just kept alternating things to change it up, stave off boredom, and power through.
One thing I will say about short runs is that on any given individual run, they may give you a false positive in terms of being really, really efficient. If you have an exceptionally good 5 minute run and then just multiply that out by 12, it can seem by extrapolation that you are getting really high xp/hr. However, do 12 of those same 5 minute runs with all of their up and down variation (some being better than others), it starts to average down to match your longer 8-10 minute run zone setups.
Any rate, if you track enough runs, all these zones begin to even out quite a bit - anything that includes Keep Depths II, Arreat Crater 2, Fields, Rakkis will do quite well -- add in the other high-ish density zones in Act III for fun / variation. Honestly, more than zones, the best things you can do for efficiency are:
a ) run with xp gear (max xp gem in helm, two rings on you, and at least one ring on follower - hellfire/leoric's)
b ) run with 24% movement speed
c ) pick a build that focuses on max movement increase skills and uptime
d ) run at a MP that allows you to one-shot most white mobs and kill packs in 3-5 seconds
e ) don't backtrack, don't swing back and waste a cast on less than 4-5 white mobs, don't try to full clear a zone
f ) do keep moving forward always with minimal stops for casts
g ) if you are focusing on xp primarily, then only pickup items that have a chance of rolling for a big sell - legendaries, gloves, wrists, amulets, rings, and certain ilvl 63 1h weaps - or if you are max xp or bust, don't pick up anything. Personally, I always ran MF capped and picked up the above noted items.
Zones and mob density certainly matter (which is why Act III has become the de facto standard for efficiency). But, once I got it parsed down to the 7 or 8 zones worth running, focusing on actual spec, gear, and run mechanics was the thing that had a far larger impact on my efficiency versus any slight changes to which of the high density zones in Act III I ran or in what order I ran them.
All of that said, at this point, I've said screw efficiency (easier for me to do now playing inefficiently isn't a double-whammy on XP and Item find). Right now, I'm just playing the game at higher MPs, full Act runs, and enjoying playing D3 in a way that makes it feel like a game again. If I find something good, great, if not, so be it. At some point, efficiency running just becomes mind-numbing and doesn't feel like a game anymore.
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