"The kit I received was the 4GB kit, or 2x2GB PC2-6400, that runs at 800MHz and has a timing rating of 4-4-3-15. The modules will run those timings at 1.8v - 2.1v and handle up to 2.2v without voiding the EVP (Extended Voltage Protection) warranty. The 4-4-3-15 timings are really good for DDR2. With such tight timings I wouldn't expect high overclocking rates at the stock timing; but loosened up, the result might be impressive."