I added a third 4gb identical memory stick to my existing two, bringing the goal memory to 12gb.
When with 8gb the memory was listed by win 7 64bit correctly as 1600mhz, now with the third stick in place, it's being reported as the next lower speed (whichever that is, I can't recall right now).
Is that the expected behaviour?
whats the clock speed of your older rams...if they are 1333 thats the reason when runing rams with 1333and 1600 clocks together the higher downgrades its clock speed to match the other so the 4 rams will be runing at 1333,to use em at 1600 all rams must have the same clock speed (1600),also whats your cpu,it could be the cpu limit....1st genereation i3/i5/i7 had a memory clock limit of 1333 which you would have to overclock to use rams with clocks higher than that
I've got it up to the same speed now after having tweaked the setting in the BIOS.
Memory speed is correctly reported in CPUz. Strangely, though, although CPUz reports the part number of all three sticks the same, the one I added is listed as not PC3-12800 but PC3-10600....
I wish I could put the 4th stick in as well, but sadly it doesn't fit underneath my CPU cooler with its cooling fins attached...
When you add more than 2 RAM Modules in a Motherboard, it downclocks to maintain stability since it uses more power.
It is perfectly normal to get lower clocks from adding 4 More GB's, I wouldn't worry if I was you.
^ Not had that problem for some time now. Installed 16 gigs (4 x 4 DDR3-1600 CL 7) on both my i5-750 (Gigabyte MB) and my i5-2500k (Asrock Extreme 4 MB). I just went into bios and selected XMP, Profile 1. My older E6400 W/DDR2 (OCed to 3.2), Just had to up the Dimm voltage, Bus voltage (+.05) and (G)mch by +0.05)
His problem was primarily down shifting from daul channel mode to single channel as h3sham pointed out.
As far as performance goes down clocking to 1333 from 1600 is a very small performance hit - The difference primarily only shows up in benchmarks, not in day to day performance.
Just download TouchBios(TB) from gigabyte's official site, install. When you install launch TB. The path you need is:
PC Status>overcklock>Advanced Memory Setings>System memory multiplier
set it to 16.00 done job, it's safe fast and you don't need the why! But if you need it, it's probably Gigabytes fault , i had the same problem.
I forgot.. restart the PC after saving your settings.