The military efficiency is quite similar, however, the destructive power has dropped significantly - these targeting improvements resulted in much less powerful warheads being necessary to achieve the same goal, so not only there's much, much less warheads (10000 vs 60000 at the height of cold war, and "only" 3000 of those 10000 are available at short notice) but also each warhead is much less destructive, the "default" warheads have gone down from multiple megatons to 100-150 kilotons.
This means that an all-out war will not only have much less fallout than in 70s, but also much less civilian casualties, much less destruction of cities, etc, etc. In the 70s, if a military base near a city would be targeted, then the city would be eliminated along with the base; now it'd likely be targeted with just something like 100kt bomb with much smaller impact; if the target was in the middle of the city, then most of the city would survive.