With their recommended voltage rating of 2.2V the modules had no difficulty reaching 1040 MHz with 5-5-5-15 timings, reaching an impressive PC2-8320 rating -- WELL above the module's PC2-6400 rating. Of course, the higher latencies took their toll, and I'd personally run these modules at their rated 800 MHz with the amazing 4-4-3-8 timings.



Link: Neoseeker