Russia had incredible fast, though uneven growth comparable with China's today in terms of percentage of GDP, this is from Kennedy's work.
I'm not so sure why I make the Russian civil war and its aftermath sound simple, the point is that out of all the complexities the Russians manage to not only pull Russia proper back together but most of the Tsarist empire as well, and could have easily gotten even more of it back.
One needs to be careful about Russian growth. AH had more real growth than Russia even prewar, but that was in the economy as a whole. Russian growth was focused on military related industries: metallurgy, infrastructure, ship building, weapons/equipment manufacturing, etc. Much if not most was funded by the French or foreign companies that operated subsidiaries in Russia. Much like China today Russia had little in the way of original R&D going on and had to import experts and modern machines to build anything modern. Even during the war the Russian industry was only able to expand as it did thanks to imports and the organization of industry by British and French experts brought in to correct the massive inefficiencies and waste going on. Pre-war the Germans were the largest group of foreign experts/foreign companies operating in Russia. It remains to be seen how Russia would have been able to operate in the world economy without the massive influx of foreign loans/experts that occurred during the war. If anything, as I've stated in other threads, Russia would be like Nationalist China-lots of uneducated peasants; a growing, beaten down, poorly paid industrial worker class; and the rich oligarchs that are intensely corrupt and have an incestious relationship with merchants/business.
AH is going to change in 1917 with the death of Franz Josef and the rise of Franz Ferdinand, as well as the issue of the Ausgleich renewal. Basically FF intended to break the Hungarians through implementing universal suffrage after taking Budapest in a quick coup after dismissing Tisza. Massive changes thereafter will see large changes for the better in AH, but long term there will be major issues in the Austrian half of the empire, as the people there will demand universal suffrage as well, with proportional representation of ethnicities and economic classes. Still they will continue to industrialize and probably would do so even quicker without the Hungarian nobility opposing any change in the feudal empire they had built up in their half of the empire. AH will probably be able to push off real reform to the Dual Monarchy because of economic growth. It'd also be interesting to see what happens when the Hungarians aren't able to maintain a protectionist policy for their grains; I suspect that many peasants in Hungary will end up with their own plots, which will be more productive than the large estates amassed by the very few powerful families like the Esterhazys. We might even see a native middle class emerge in Hungary as a result (OTL the middle class was only 25% Hungarian; it was mostly Jews, Germans, and Czechs-those groups educated enough to participate in early industrialization/trade in Hungary).
Germany has already sort of peaked, but has some growth potential left in the colonies. Cotton production and rubber were just starting to come online in East Africa, so there was potential to turn those profitable. The big change is going to come with the introduction of universal suffrage and governmental reform that would see the Junkers' influence destroyed and the ending of agricultural tariffs. Much of the reason for Germany being locked out of international markets for their industrial goods was due to the policy of protective agri-tariffs to maintain Junkers' latifundas in East Prussia. Without that agriculture shifts to more productive means and makes Germany more self sufficient in agricultural goods as a byproduct of trying to stay competitive in international trade.