According to "What are the best current lower bounds on 3SAT?", Ryan Williams has an answer that states that the (time * space) requirements for 3-SAT must meet or exceed $n^{2 \cos(\pi/7) - o(1)}$ infinitely often. See
Ryan R. Williams
Better Time-Space Lower Bounds for SAT and Related Problems
20th IEEE Conference on Computational Complexity, pages 40-49
2005
...or his link here.
If we consider Atkin and Bernstein's sieve:
A.O.L Atkin and D.J. Bernstein
Prime sieves using binary quadratic forms
Mathematics of Computation, Volume 73, Number 246, pages 1023-1030
December 19, 2003
...It requires $O(\frac{n}{\log \log n})$ additions and $n^{1/2 + O(1)}$ space. So does this sieve alone meet the time/space requirements for 3-SAT? Or are the results inconclusive for the sieve?