can somebody explain this

[exodusprime1337]

so i built a new rig a few weeks ago. and i had it set up 12 hours prime stable like this

phenom 2 940 @ 3.817Ghz 217x17.5
2x1gig ddr2 1150 @ 1160 5,5,5,15,2t 2.3v
nb x12 or 2604 @ 1.375
htt @ 1980 or so, stock volts, 1.2 or whatnot

now all i changed was i purchased a 4 gig kit of memory from g.skill and here's what i've done

i installed the memory, cleared cmos and started pc
set latency to 5,5,5,15 and voltage to 2.28(only requires 2.0)
left everything else the same to achieve 1160Mhz memory, but i dropped the cpu multi to 10 so that i wasn't stressing the cpu,
i ran occt/memtest/prime(for 3 hours) at this setting and was fine.

so i restart and up the multi on my cpu back to 17.5 for the 3.81Ghz setting and now my pc is no longer stable here, it will boot to windows, allow me to do basic light duty work but as soon as i start a game, i get a blue screen....

my question is why... i've tried everything except up the cpu voltage, i mean i'm at 1.50 as it is, and temps in prime hit 54 or so and i'm not sure how much higher i can let that go on air. but i dont' see how the 2 gig kit(1x1gb) works fine at that oc, and the 4gig kit(2x2gb) does not. i've had to drop my 3.8ghz oc down to 3.7 righ tnow just so i can stay stable??

 

[Mussels]

more ram = more stress on northbridge (memory controller)

Work on NB/mobo voltages, not CPU.

 

[r9]

I guess you should increase chipset voltage because of 4gb instead of 2gb.

 

[technicks]

Yest that would be my gues to.
In my previous MSI P45 board i first had 2x1 Gb and i could leave the nb voltage at auto.
After stuffing in 4x1Gb Team Xtreem i had to up the nb voltage to 1.38 to get 3.6Ghz stable.

 

[exodusprime1337]

i've tried all of that, all the way up to 1.5nb and 1.48 cpu nb, i've got them all up, if i drop the cpu down a mere 50mhz all seems fine. i just don't get it, it's odd.

on another note, i never really researched this but i was wondering what is the max temp i should stay under. only in prime do i ever go over 50, in games i usually go to 42-47 tops.

 

[r9]

i've tried all of that, all the way up to 1.5nb and 1.48 cpu nb, i've got them all up, if i drop the cpu down a mere 50mhz all seems fine. i just don't get it, it's odd.

on another note, i never really researched this but i was wondering what is the max temp i should stay under. only in prime do i ever go over 50, in games i usually go to 42-47 tops.

That are low temps you are getting. I think around 60 and you OK.

 

[technicks]

And if you drop the memory speed can you get 3.8Ghz stable then?

 

[inf3rno]

Temps are fine. And congratulations you have entered in the complex zone of overclocking.

 

[technicks]

I think he knows his share of overclocking.


Btw. Why do you set ram to 2.28 if it requires 2.0?

 

[exodusprime1337]

because my 4 gig kit only requires 2.0 for 1066 but i've been testing it at 1280-went 6 hours stable, and i want to keep it around 1160@2.28-2.34v. no more then that

it's cool running, my ir thermometer puts the heatspreader at about 28c under full load, so i don't mind pushing it a bit.

as far as the oc. i managed to get here to 3.8 by changing a setting i've not seen in my previous boards, a vdda setting. i moved it up from auto to 2.72 and we seem to be ok

i have no more time to stress test for the night, i'll continue in a about 18 hours when i get back from sleeping/working. keep an eye on this i value your contributions. and if someone can tell me what the heck vdda does, i'd be super happy, it seems to be working, but i don't know how or why lol.

 

[technicks]

VDDA, VDD, and VLDT are considered RUN planes and are
powered in the S0 and S1 states only

basically what happens to the voltage when a load is applied on the CPU is the voltage actually drops. so if you set your voltage to say 1.45v in BIOS and the CPU VDDA is set to it's lowest setting, under idle conditions, the voltage should be around 1.45v. however, under load, the voltage will actually drop below your setting of 1.45v. how much depends on the make and model of your motherboard.

setting the CPU VDDA to it's highest setting will cause the CPU voltage to be (alot) more than what you set it to in BIOS. for instance, if i set my CPU VDDA voltage to 2.80v (Auto, 2.5, 2.6, 2.7, and 2.8v are the settings on my ATI chipset), under idle conditions, my CPU voltage will be about 0.04-0.05v more than what i set it to in the BIOS. while under load, it can go as high as 0.10v over my BIOS settings.

it does this to make sure that your CPU is always getting a good amount of power so that the power doesn't dip down and cause BSOD's. usually setting it to AUTO is fine as it will use the lowest settings while under idle and use the highest settings while under load. this makes it so that your not wasting too much power and/or over-volting your chip at idle while making sure under load, you're receiving enough power.

Hopes this helps a bit.

 

[exodusprime1337]

well well, technicks saves the day, i couldn't find that info. a quick update, i've dropped my nb from 2750 down to somewhere close to 2600 and am making progress there, despite throwing almost 1.5v at it to try and stabilize it. i also went from 218x17.5 to 215x17.5 netting me only 50Mhz loss, which really isn't going to kill me. this will keep me going till the weekend where i guess i'm gonna have to open up the windows in the 0 celcius environment i live in and go to it and come up with an answer.

but two my point, the differences between stable with 2x1gig vis 2x2gig still perplexes me. let me know if anybody finds or comes up with an idea, i'm open to all suggestions.

l8r tpu, i gots to sleep.