With a knife in CS:GO.

Edit: sv_noclipspeed 5 doesn't do anything that you'd assume and everything here is wrong. Valve, pls fix.
Speed with knife = 250 units per second

sv_noclipspeed = 5 multiplier of units

Speed at noclip with knife = 5 * 250 = 1250 units per second

1 m = 0.01905 units

Distance from earth to sun according to google = 149,600,000 Km = 149,600,000,000 m

Distance from earth to sun = (149,600,000,000 / 0.01905) = 7.8530184*10^12

Time to reach earth to sun = 7.8530184*10^12 / 1250 = 6282414720 seconds = 104706912 minutes = 1745115.2 hours = 72713.1333333 days = 2423.77111111 months 

= 201.980925926 years