FX-4100 - OC'd 4.6ghz
Gigabyte 990FXA-UD3 AMD990FX
Corsair Vengeance 2X4GB - 1600mhz
Sapphire 5850's Crossfired - OC'd 891mhz/4700mhz
Corsair Cooling Air Series A50 Performance CPU Cooler
CX600 Corsair PS
Antec 300 Case
My system is very stable at the current settings (above). So I figured I would try to push it further by overclocking my RAM. I have read that the Vengeance should overclock up to 1900mhz with just a voltage bump to 1.65V. I tried bringing it up to 1866mhz and bump the voltage to 1.65mhz and it wouldn't boot. So I tried relaxing the timings, still won't boot. I notice on the reviews the system generally has an Intel CPU/MOBO. Is there a trick to overclocking RAM with an AMD setup? Specifically a Bulldozer setup?
When you go up on the expected memory speed make sure your uncore clock ratio is twice what the memory speed is. Memory speed set to 1866 - uncore clock ratio 3732. It's always a little difficult when the cpu is overclocked due to the memory controller also being stored on the cpu. I'm not familiar with the FX boards but can you increase the cpu/pll voltage a little?
You will probably need to go up on the QPI/VTT voltage. The higher you overclock the memory the more the memory controller is going to need power. And of course you will need to increase the memory voltage a little bit as you go up in speed usually.
Your probably not gonna get anymore than 1750 MHz out of that RAM if your lucky...Where did you read that you could get it to 1900 MHz? Thats a load of BS....to get to 1900 MHz you would have to loosen your timings at least by 2 clock cycles on the CAS, RAS, etc.....and even still that might not work..It would be better to try to tighten the timings at 1600 MHz..What is that CAS 9 1600 MHz RAM? If so even CAS 8 at 1600 MHz is equal to CAS 10 at 1866 MHz..Lower latency is where you see real life performance increases
So heres how it looks:
DDR3 1066 CAS 5 = 1333 CAS 7
DDR3 1333 CAS 7 = 1600 CAS 9
DDR3 1600 CAS 9 = 1866 CAS 11
So if you could bring your CAS down to 7 @ 1600 you would have the equivilent of CAS 9 @ 1866...and put the voltage around 1.6v ...1.65v is on the verge of cooking it
No giving those choices 1800 MHz @ CAS 8...Yet you have CAS 9 1600 MHz...So if you wanted the same performance out of the RAM you have I would try either CAS 8 or CAS 7...bear in mind when messing with the RAM timings you may have to reset BIOS countless times until you find the sweet spot....
Your RAM is Corsair Vengeance CAS 9 @ 1600 MHz at 1.6v stock correct?....Well your best bet would be you just keep the RAM at 1600 MHz and tighten the timings...BTW you were lucky that it booted at 1700 MHz to be honest..your board may have loosened your timings up automatically to get her booted at 1700 MHz....If you want 1866 MHz RAM and you want it stabile you are gona have to buy 1866 RAM...In order for that system to even attempt to boot at 1866 MHz with that RAM you would be chasing the dragon's tail to get the timings right....It would at least be CAS 11 or higher and really its just a crap shot and more likely than not with that RAM its not gonna be stable at 1866 MHz even with the upped voltage and loose timings
Try 7-8-7-24-1T @ 1600 MHz ---> 1.6v
Just remember to keep a log book handy when playing with RAM latencies