Now on all the overclocking threads i've read this is one of the most common questions:-
My Asus Motherboard does not have a 1.65v option for DRAM, only 1.64 or 1.66, but if i go above 1.65v I get a warning saying Intel warn it could damage the CPU.
Now most threads say just ignore the warning and go with 1.66v. But why would Intel go to the bother of warning everyone, and why would ASUS leave out the option of 1.65v.
I've seen a few explinations;
1) asus designed the board in a rush and accidental left the option out.
2) its a conspirency between intel and asus so that to get your DRAM stable you have to decrease the life of the CPU so you have to upgrade sooner.
3) There is no differnce between 1.65v and 1.66v on an asus board and that asus boards read 1.66v as 1.65v.
4) The reason Intel says 1.65V max is because they want you to keep it within 0.50V of the CPU Uncore voltage, something listed in BIOS as QPI/DRAM voltage. ?
I think number 4 sounds the most plausible, at least it sounds the most scientific, but unfortunately I have no idea what it means. Whats your thought and more importantly your experience with going 1.66v or higher?
Forget #1 and #2. Gigabyte also only allows for increments of 0.02 V. I've seen #4 a few times and many experienced folks push it.
Here's my question: why not just set the RAM at 1.64V, test it for stability, and leave it be? Often boards will give a little more than are set anywhere, at least according to the software that measures it.
CPU-Z doesn't show what V your RAM is using? Are you looking at the SPD tab of CPU-Z? That shows what the RAM chip specs contain. Which leads to the next question, if your RAM chips say it should be running at 1.5V, why are you upping it to 1.64? Maybe there are multiple values listed? Please post a screenshot, and a link to your RAM.
Sparrow, you never mentioned - what problem are you experiencing? Is it stability with the RAM?
The RAM you have is not realy intended for the Bloomfield or Lynnfield (i7s, i5s, or i3s). According to the link you posted, it's 1600 MHz frequency was "tested to run ... at 1.7V to 1.9V." So it could take upwards of 1.9V to get it stable at 1600 MHz which is not recommended for the new platforms.
If stability is your issue - if you can't get it stable at 1600 at around 1.65V, back it down to 1333 MHz and make sure it's stable. Then you can slowly lower the multipliers, for example start at 9-9-9-27 then lower to 8-8-8-24. The real world performance difference between 1600 and 1333 is not really noticable anyway: http://www.tomshardware.com/reviews/memory-scaling-i7,2...
so currently i have DRAM frequency showing as 725MHz in cpu-z and timing 8-8-8-24 74 1T.
NB frequency is 2901.9Mhz.
I seem stable in games and everything except prime95 which reboots my pc after a hour.
You double the DRAM frequency to get the actual speed right? so mine's running at 1450MHZ, is this correct? so this is a bit faster then the 1333 you mentioned?. At this speed I'd only need the voltage at the standard 1.5v or maybe one notch up.
Reading the post you linked i'm surprised at how little difference there is in real life apps. so I might just switch back to 9-9-9-27 and play it safe. If I leave everything on auto in the BIOS it'll sort it all out for me and should be stable i think. Or am I getting really confused?
Yes, you're at 1450MHz, a little faster than 1333 MHz. Shouldn't take much more V to get stable, but of course everyone's experience is difference as ultimately each piece of hardware is different.
You could set it all at BIOS and it'll sort it out. But now that you know as much as you do, I say go ahead and set it yourself.
My other recommendation, given the stability issues, is to set it to stock timings, back to 9-9-9-27, and test again in Prime95. Get it stable first, and then start tweaking things. For one, the RAM change won't make a whole lot of difference. And the better reason is once it's stable if you start making small tweaks and it becomes unstable you know exactly what caused it and therefore what problem to address.
For example, you may find it's not the RAM but the CPU that's unstable. A slight bump in Vcore might help. But again, go for stability at lower settings first and then when you make changes you'll know what caused the problem.