This happened to me with my G.Skill & Xtreme modules, problem? Subtimings, where it says 5-5-5-16-35-10--10-11....that 35 was at 25 which the HK were able to take but the Xtreme weren't, so I had to up them to 35 and the cool thing it didn't change in performance.
And right now I'm using 4-4-3-5-35-10-10-10-11. Check in CPU-Z and check for the tRAS & tRC under the SPD tab. Usually at 400mhz the timings should change and you'll see. Remember, they're pre-programmed differently because of speed and ICs.
Now, if that doesn't help? Time to get some G.Skill, I ditched my Corsair modules two years ago and I am not getting Corsair unless it's the v1.1 but those are too pricey, the rest are not as good IMO.
Bookmarks