Short answer: from 1945 to the late-1960s, pretty good; not very powerful in the 1970s; completely obsolete by the 1980s. The Soviet industry developed at about the same pace as the West until about 1969, which is when the Soviet government terminated independent Soviet programs in favor of attempting to copy/pirate IBM.

As of the late-1980s, Eastern bloc computers were at least 10-20 years behind the West (and Japan). In East Germany for instance, university labs would only have "one 8-bit Sinclair Spectrum with 64K of RAM for every 10 to 15 scientists." This computer was released in the UK in 1982 and only sold for £125, which obviously placed it within the range of the home computer market. Eastern bloc scientists, more or less, only had a few hours access per week to the same computing power as an average British consumer.

At the top-tier of computer development, Soviet scientists in the mid-1980s were developing supercomputers capable of 100 to 10,000 megaflops. In contrast, Americans had developed machines capable of 1.9 gigaflops by 1985. The STAR-100, a machine developed by Control Data Corporation (Minnesota, USA), hit 100 megaflops in the early-1970s.

Tracing languages is a bit outside of my knowledge. A journalist in the late-1980s visited a school in Novosibirsk, Russia, and reported that students learned BASIC, ALGOL, FORTRAN and PASCAL, although the latter was only theoretical as no computers in the school could handle it. He also reported his portable Toshiba 1100 Plus PC was more powerful than the single computer shared by "300 students in Novosibirsk." Granted, these anecdotes are likely exaggerated by the politics of the time, but surely some there are some truths to the statements. Also, the Soviet consumer computer industry was virtually non-existent compared to western Europe, America, and Japan by this point.

Disclaimer: I do not claim to be an expert in this field, but I do research the history of gaming and computing in 1970s/80s America. I hope this is a good start to get discussion flowing.

Sources:

• Frantisek Janouch, "The Crisis in Soviet Computer Science," The Scientist, Mar. 21, 1988. Link
• Marshall Yovits, ed., Advances in Computers, Volume 30 (Boston: Academic Press, 1990).
• Loren Graham, What Have We Learned about Science and Technology from the Russian Experience? (Stanford, CA: Stanford University Press, 1998).

Also was there exchange and collaboration between computer scientists in the East and West?

On a related note, did the Soviets have their own precursor to the internet like DARPAnet in the US? Did they develop their own networking protocols, or did none of that sort of thing come into Russia until after the collapse of the USSR?

Follow-up question: in an episode of Deutschland 83 (set in 1980s East Germany, not necessarily just 1983), a Stasi computer technician does not have a computer of Western architecture available for some agency task. His frustrated superior orders a single part, with implied hardship, which is then integrated into a Soviet architecture computer.

Would this be realistic? Did the same technological gap exist for the Stasi as well as the Soviets? Did the Stasi confiscate or smuggle higher quality computers into the country for their own use?

As an ancillary question, I've heard that the Soviets experimented with trinary logic and were interested in VLIW for longer than architects in the west were. If anyone has a good place to look up more information on these topics I'd be interested.