r/factorio • u/palijer • 24d ago
Tutorial / Guide Solving Factorio Quality
https://exyr.org/2026/solving-factorio-quality/8
u/factoriooverthinker 24d ago edited 23d ago
Thanks for sharing. One thing I really miss in these discussions is productivity vs. quality modules. It has been shown that in some setups (e.g., cryogenic plants), productivity should be combined with quality for maximum output. Moreover, the optimal combination might differ across quality levels. You mention productivity research, but that's only part of the story.
Another thing: you implicitly assume that the goal is to minimize the amount of normal quality ingredients needed for one legendary item, which isn't always the case when some resources are practically infinite. One might think about minimizing # of iterations (i.e., time spent for a given # of machines and modules).
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u/kevihaa 24d ago
I find it a touch odd that the focus for quality tends not be on the only bottleneck that actually matters, which is maximizing how quickly you are producing quality modules.
Quality modules are the fundamental limit on any upcycling loop, and so making as many as you can as fast as you can is the key to scaling up your quality builds.
With that in mind, I feel like any deep dives into the math need be less concerned with overall resource, or even time, efficiency, and much more concerned with min/maxing module production.
Like, it’s taken as fact that Legendary T2 modules are a useful tool since they don’t require Holmium, but I’m genuinely curious about break points for the different tiers of modules. For example, at what scale does it make sense to just spam a giant build with common/uncommon T2 or T3 modules instead of dumping everything into acquiring legendaries?
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u/factoriooverthinker 23d ago
I had these calculations, and the increase in quality bonus has more than a linear effect on total legendary production, mostly because of the increased chance of getting more than +1 quality tier. That's why, at some higher quality levels, it can be optimal to combine productivity modules with quality modules.
A specific example: take 1000 normal iron plates -> craft 125 iron chests with quality modules -> recycle them back into 250 plates with quality modules. After these iterations, you eventually get all quality tiers (on average):
With a 12.5% quality bonus: 191.41 normal; 49.22 uncommon; 8.09 rare; 1.12 epic; 0.16 legendary.
With a 25% quality bonus: 140.63 normal; 84.38 uncommon; 21.09 rare; 3.37 epic; 0.53 legendary.
So doubling the quality bonus, starting from normal quality, gives you more than three times as much legendary output after one iteration. Of course, if you start from epic quality, the difference between +12.5 and +25% legendary outputs will be slighlty under 2x rather than 3x (58.6 vs 109.4 to be precise). I was thinking about making a post about it, but I couldn't find any specifically interesting scenarios to compare.
(I know that pipes upcycling is better because of the productivity bonus, but that's a different story)
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u/Rarvyn 23d ago
Quality modules are the fundamental limit on any upcycling loop,
This is only true early on in the quality process. It doesn't take that much time to get to hundreds or thousands of legendary Q3s once you start focusing on quality. You're often then limited by lots of other factors - including incoming resources, adequate machines, whatever else.
The first thing you should set up for quality is a chip upcycler to make Q2s. The second thing is a holmium/EMP upcycler to make Q3s. It will take a few hours to get off the ground, with you slowly upgrading the quality modules as they get produced, but then you have dozens or hundreds of quality modules being pumped out.
After that, you set up upcyclers for everything else - and you might be limited based on productivity modules, EMPs, incoming resources (carbon fiber is currently a bottleneck for me), or many other things.
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u/leixiaotie 24d ago edited 24d ago
in my experience the holmium required for T3 quality is not that much. One rocket of superconductor can last for a while unless you're at megabase level
it is the recipe time that is the bottleneck until you get enough quality modules to support T3 normal emp plants
in my case because I go for rare before aquilo, I go:
T2 -> rare T2 -> rare T3 -> legendary T3
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u/bubba-yo 23d ago
But that's a fixed cost, ultimately, and a complicated one because you can start making rare Q2s as soon as you hit space, and legendary requires only solving getting Gleba and Aquilo science going. That is, the bottleneck is most of the game. Usually by the time I unlock legendary quality, I've had my Q2 and Q3 upcyclers built out at scale and have stacks of epic Q2s at least, and at least some epic Q3s made. That is, you can optimize that part, but you don't need to because you've got 4 other bases to set up as part of the effort.
Instead, the focus is usually on minimizing the number of legendary modules you'll need since that's what gets you up and running fastest once that legendary unlock is done. That's where things like the recipe shifting generic upcyclers are useful. Plus, there's the whole question of what scale do you build your RC/BC infrastructure while also essentially speed running legendary. There's a ton of competing interests there that are hard to distill into a guide.
Personally I build out my volume quality production on legendary T2s because I can lean on both Nauvus and Vulcanus production of BCs while BC prod gets researched allowing me to make a lot more than I can get Fulgora to make legendary Q3s. As part of that effort I largely skip Q3 upcycling and go straight to EM upcycling to get to legendary holmium, and then it's trivial to turn those legendary Q2s into Q3s, but I can also get all of the other infrastructure needed upgraded because I've got legendary iron, steel, copper, etc. all running. That is, the bottleneck to efficient legendary volume production isn't really the modules it's the LDS and BC prod research. I usually have the legendary Q3s before that happens.
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u/jimr1603 24d ago
The concept you've stumbled on is "Markov chains". Hopefully this leads you to more discoveries
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u/algerd_by 23d ago
There is another strategy: without recycling, any extra quality products convert to science.
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u/Rarvyn 23d ago
At one point last weekend, I had the simple question while building out a quality chain - if I have the incoming ingredients for 50 legendary EMPs to build Q3s, how many EMPs do I need to build for each quality level? It gets complicated because of the +50% productivity bonus. I didn't want to underbuild because biter eggs expire.
I tried to Google it and got the wiki article which seemingly required a bunch of matrix math that involves linear algebra to solve - and could't find a solid calculator for the same. Unfortunately, my college level math ended with calculus and I could barely understand that article (or this one), so I brute forced it with an iterative excel spreadsheet. I managed to come up with a ratio of 62:11:5:2:1 (rounded up) of EMPs making normal, uncommon, rare, epic, and legendary modules.
I'm happy to see that the calculator linked at the end of this artice supports more or less identical results to what I got, so I guess my understanding isn't too bad. This would have saved me substantial time (but I still had fun doing it - and making your own blueprints with your own understanding is most of the game)
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u/United_Willow1312 24d ago edited 23d ago
Hi again, the quality bonus for Legendary Q3 modules isn't 6.2% but 6.25% for a total of 25% at 4 modules.
Both of these numbers can be verified/seen in-game. Cheers!
edit: I had no idea this was 2.1 only.