5V line for vcore

vcore is drawn from the 5V line, right?...if it reads 4.81 on a 2400MHz oc (the -5.00 reads -5.12)...is that what would cause a system lock up on P95 after a couple of hours? that's the only thing i can think of. mem's in the sig at 6/3/3/2 on 2.8, that's as high as i can go (vdimm). i can fold for days (and run Stress CPU, Burn K7 for hours) but P95 locks up after a couple of hours, so i'm trying to get it stable for a min of 24 hrs since P95 is THE stability test we all use to check our systems....i don't bother w/3D2001 or sandra cause those will last for hours/days on rigs that can't fold....thanks all.

ps. i'm running 11.5X205 now because of the P95 issue...F@H (w/gromacs) continues unscathed....already tried resetting cmos and all the other usual tricks....

What Vcore are you running and how stable is it? I would worry about the Vcore itself more than the +5 volt line.

A7N8X, 8RDA+ use 5V to generate Vcore. NF7-S, 8RDA3+ use 12V.

For A7N8X, the 5V current is mainly for CPU, plus motherboard, part of HD, optical drive, video card also uses 3.3 and maybe 5V. From your sig, a 350W PSU is at the edge of handling a Tbred B at 2400 MHz. You may need a good, bigger PSU perfrerably with tigher line regulation to handle higher overclocking (if it is a main objective than price-performance for the 100-200 MHz more).

Don't border with those negative voltages -5, -12V, ...

Sometime locked up under load may just require Vcore increase by a step (25mV) to resolve it. It may or may not be a PSU problem.


Some results on PSU with different ratings for overclocking

Does anyone know what line a Biostar M7VIG PRO draws it's vcore from. And how many amps shold a 500 wat PSU be puting out on the 12v line?

I'll ask my question in this thread.

I have now this new rig and CPU speed at 2159MHz with 1.8V. Now I tried 2280MHz with 1.85V earlier and it would crash at loading windows. I raised it to 1.9V and it didn't even post (had to clear CMOS, insert trick didn't work). Now as I write and running Prime, Vcore shows ~1.74-1.76V and +12V shows 11.67V. Vcore is 0.05V off of the desired and +12V would seem low. Before I built this into case and were running idle, stock at bios screen it was 11.67V too. I measured with multimeter and it was 12.15V. Is my 300W Enlight holding my OC back?

Where did you measure at? If you unplugged the atx cable from the mobo and measured, then yes, your PSU is. It's not good when your 12v line is low. It causes serious stability problems. I suggest you upgrade to a better PSU.

If you measured from on of the (Brain just died) other power cables (the type that plugs into your HDD) then your PSU is fine. Now you have to check the ATX cable where it connects to your mobo. Your connector is not transferring its voltage as well as it's supposed to. I don't know how to fix this. A new PSU may or may not fix that.

breez said:

I'll ask my question in this thread.

I have now this new rig and CPU speed at 2159MHz with 1.8V. Now I tried 2280MHz with 1.85V earlier and it would crash at loading windows. I raised it to 1.9V and it didn't even post (had to clear CMOS, insert trick didn't work). Now as I write and running Prime, Vcore shows ~1.74-1.76V and +12V shows 11.67V. Vcore is 0.05V off of the desired and +12V would seem low. Before I built this into case and were running idle, stock at bios screen it was 11.67V too. I measured with multimeter and it was 12.15V. Is my 300W Enlight holding my OC back?

Click to expand...

We can't say for sure unless you test with a multimeter at load. But there is a good chance it is.

Jarhead: 4.81v does seem quite weak for a 5v line. But try increasing the vcore by .025v and see what happens.

I would have to say its your PSU, I had a very similar problem with some gerenic 300w psu... i got a 530 Fortron and it rocks!1

@ 2466mhz on my 1700+ my 5v was 4.91-4.94.... thats VERY stable!

Adam

thanks...that's what i figured. i can only get up to 1.75V. i read that if i mod my chip to make it a 1.65V default, i'll be able to get up to 1.85V on my board...correct or not?

Jarhead7236 said:

thanks...that's what i figured. i can only get up to 1.75V. i read that if i mod my chip to make it a 1.65V default, i'll be able to get up to 1.85V on my board...correct or not?

Click to expand...

In my case, the A7N8X bios adds a max of 250 mV on top of the minimum Vcore after Vcore mod.

E.g.
1.5 V min, range = 1.5 - 1.75 V
1.75 V min, range = 1.75 - 2.00 V

yeah, mbm and bios read 1.78-1.8 (when at 1.75V) but still the lock up after a couple of hours....that's the only thing bugging me. maybe i should be happy just folding w/out problems. either way, i'm waiting for someone (i'm not a risk taker) to do the L12 mod on an a7n8x board to see if i'll get any benefits from that....still the question, will the mod to make 1.65V default give me the 1.85V option? i can't remember where i read that...thanks again.