1866Mhz 9-11-11-28 1.6V vs 1600Mhz 9-9-9-24 1.53V?

[sherlockwing]

Hi, I was attempting to overclock my 4 sticks of Corsair Vengeance 4G DDR3-1600 Cas9 1.5V Ram on my ASRock Z77 Extreme 4 board(system in my sig), with all Timing set to Auto.

Command Rate in both cases is 2T

First My Ram would not pass Prime Blend at 1600 Mhz 9-9-9-24 @1.5V(I would get individual core failure yet no blue screen) though it would pass Memtest86+ v4.20 without problem, so I raised the Dram Voltage to 1.53V and run Prime Blend(1hr 45 min) and Prime Custom(1 hr) Torture(14G Ram used) , passed both.

I first tried to raise the XMP profile to DDR3-1866 with the voltage unchanged(1.53V), this failed Prime Blend in 4 min.
I upped the Voltage to 1.56V, this failed Prime Blend in a few mins as well.
I upped the Voltage to 1.6V(1866Mhz 9-11-11-28 1.6 V ), this passed 30 min of Prime Blend then I shut the test off

I tried to set the timing in Bios manually(from the auto 9-11-11-28) to 9-9-9-24, you probably know what happened, this stupid move caused my computer to auto shutoff during boot.

I pressed Clear CMOS button, rebooted and went back to DDR3-1600, 9-9-9-24 at 1.53V and all is well.

My questions:
1. how much extra performance do I gain at 1866Mhz 9-11-11-28 1.6 V vs 1600Mhz 9-9-9-24 1.53V? I don't mind being a min slower in video encoding but if it affects my gaming performance I might take the 1866Mhz.

2. Is the extra Dram Voltage an issue(I hear you are fine at anything below 1.65V, but the board allows a max of 1.8V)?

3. I plan on stress testing my OCed Ram with a longer Prime Blend & Prime Custom 14G Ram run(each for an hour) and a Memtest86+ run, is this sufficient and if not what else should I do to test my Ram.

4. I hear that not OCing your Ram reduces your CPU OC ceiling by about 200 Mhz, is this true?

p.s If you have experience OCing 4 sticks of Ram, how much could you push it? Do you recon I can push mine to 2100/2133 at 1.65V?

 

[Herr_Koos]

Quite frankly I very much doubt you will notice the difference, even if you leave the RAM at stock speeds. The Bulldozer AMD platform benefits from faster RAM based on benchmarks, but Intel platforms do not as much. You system is plenty fast as is and does not need a minor bump in RAM speed.

 

[sherlockwing]

Quite frankly I very much doubt you will notice the difference, even if you leave the RAM at stock speeds. The Bulldozer AMD platform benefits from faster RAM based on benchmarks, but Intel platforms do not as much. You system is plenty fast as is and does not need a minor bump in RAM speed.

OK, unless it really affect my gaming performance(seems like this is a non-issue) or OC ceiling (4.6Ghz is my target) I think I will be comfortable with DDR3-1600 9-9-9-24 1.53V, might try explore to see if I can get it stable somewhere between 1.5V which failed prime and 1.53V where it passed.