A Core-i7 2600 has a die size of 216mm^2.[1] Assuming it's close to a square, that's about 14mm on each side. Electrical signals in a CPU travel almost at c, so at 3.4Ghz, signals can go across the die 6 times.
It's probably much less than that because paths in the CPU aren't straight lines. Also the i7 is a 4-core die, so it's unlikely that any signals need to go across the entire die in one clock. (Besides the clock signal, of course).
Check out the animations under "Clock Distributions" (numbers 19 to 25. It shows how the propagation of the clock across the die is affected by frequency (When a part of the fabric/tree is up or down it represents 1 and 0 respectively).
My favorite is the SymTree and Non-Uniform SymTree (23 and 24) which shows how having a non uniform load at various parts of the chip and a fixed tree structure affects how long each part of the chip is at a 1 or 0 state (i.e. a low load part of the chip will spend more time at a stabilized 1 or 0, while a heavy capacitive load at one part can not even reach a true 1 or 0).
It's probably much less than that because paths in the CPU aren't straight lines. Also the i7 is a 4-core die, so it's unlikely that any signals need to go across the entire die in one clock. (Besides the clock signal, of course).
[1] http://en.wikipedia.org/wiki/List_of_Intel_Core_i7_microproc...