AI capex is so big that it's affecting economic statistics

Can you annualize Nvidia's Q1 results simply by multiplying them by 4?

For a first approximation, yes? Their earnings have been growing steadily for years ($4-5B growth in each of the last 8 quarters), with no seasonal effects.

Q1*4 is highly likely to be a better estimate of their eventual 2025 calendar revenue than their current trailing 12 months revenue would be. Probably still a bit conservative, but easier to justify than projecting that growth continues at exactly the same pace.