If you're going for objective performance measures, a study reported that for on-screen text, longer line lengths (approx 100+ words) supported faster reading and medium line length (55 characters) for better comprehension.
However, subjective measures indicate that people prefer a more moderate line length. On columns: "a single wide column is read faster, but narrow multiple columns are preferred". Multiple columns are actually judged as easier to read and contribute to the screen being judged more organised and offer visually interesting texts.
Dyson, M.C. How physical text layouts affects reading from screen. Behavior & Information Technology 23, 6, (2004), 377-393
Braganza, C., Marriott, K., Moulder, P., Wybrow, M., & Dwyer, T. Scrolling behaviour with single- and multi-column layout. WWW '09, (2009), 831-840.