I have read the history of the RSA-129 challenge, and now I would like to know if it would be possible to factor RSA-129 with a single "average" personal computer, today. Has someone tried to do this particular factoring?
From what I can gather it took about 2.5 months to factor a 512 bit RSA key on a personal computer from 2009 with a dual-core athlon64.
A typical desktop of today has about twice as many cores and twice the clockspeed. So that would cut it down to about two and a half weeks.
Furthermore modern processors have better IPC and your key is less than 512 bits.
So clearly doable but probablly not instant.