Vcore and vdimm with A64

[uOpt]

however, that is definitly not a RevE proc, and that is what is affected, i think.. lol

No, this should be universal to all AMD64 processors. Same voltage dividers, same electrical connections, same diodes.

[Otaking71]

different mem controller in rev e however..it could be more voltage sensitive.

[Hound]

yeh, i thought so, as RevE is improved over the previous generation..

[ozzimark]

different mem controller in rev e however..it could be more voltage sensitive.

you can change the memory controller all you want, but it's the diodes that protect it from the VTT, which shouldn't have to be tweaked when the MC is

[NightCrawler™]

Small question based on this list....
Vdimm - Vcpu(min)
----------------------------
2.9 V --- 1.12 V (min)
3.0 V --- 1.17 V (min)
3.1 V --- 1.22 V (min)
3.2 V --- 1.28 V (min)
3.3 V --- 1.33 V (min)
3.4 V --- 1.37 V (min)
3.5 V --- 1.42 V (min)
3.6 V --- 1.47 V (min)
3.7 V --- 1.53 V (min)
3.8 V --- 1.58 V (min)
3.9 V --- 1.62 V (min)
4.0 V --- 1.67 V (min)

Is the minimum required vcore the vcore you set in your bios or the sum of the vcore + vidspecial = the vcore shown in CPUZ...??

NCâ„¢

[uOpt]

Small question based on this list....
Vdimm - Vcpu(min)
----------------------------
2.9 V --- 1.12 V (min)
3.0 V --- 1.17 V (min)
3.1 V --- 1.22 V (min)
3.2 V --- 1.28 V (min)
3.3 V --- 1.33 V (min)
3.4 V --- 1.37 V (min)
3.5 V --- 1.42 V (min)
3.6 V --- 1.47 V (min)
3.7 V --- 1.53 V (min)
3.8 V --- 1.58 V (min)
3.9 V --- 1.62 V (min)
4.0 V --- 1.67 V (min)

Is the minimum required vcore the vcore you set in your bios or the sum of the vcore + vidspecial = the vcore shown in CPUZ...??

NCâ„¢

You are confused.

The sensors at least on the DFI boards are just off, don't use them.

You get what you set in the BIOS, and it doesn't matter whether you set it in the primary control with no special or whether you mix something together with the special.

[NightCrawler™]

So regardless my combination I set in my BIOS the final output is what is shown in CPU-Z.

So my 1.425vCore should be safe with my 4000 VX Gold @ 3.3v... correct?

NC™

[uOpt]

So regardless my combination I set in my BIOS the final output is what is shown in CPU-Z.

No, what CPUz shows is too low, at least on DFI NF4 boards.

What you get is what you set in the BIOS.

[meateater]

I was using 1.42Vcore with 3.5Vdimm benching @ 3GHz then remembered this thread and upped Vcore to 1.44v, is this safe ??, this as per my sig using my new 146 that is simply an amazing chip

If it died I would cry for a week

I think you are still safe, as 3.5v / 2 = 1.75, 1.75 - 1.42 = 0.33, which is less than 0.6volts.

OT: I just got my opty 144 and its not very good... 2.7ghz @ 1.55vcore in bios. Read as 1.52vcore in ITE smart guardian, I dont have any multimeter to test with. Is this vcore thing an issue with the board? or is my Enermax PSU not giving enough juice?

[NightCrawler™]

No, what CPUz shows is too low, at least on DFI NF4 boards.

What you get is what you set in the BIOS.

Ah... now I get it... LOL Thanks for the heads up Martin...

NCâ„¢

[Kalero]

what about 2.6-2.7 on vdimm
i have my X2 3800+ @2400 1.45V
i think it's safe...

[smartasien]

hmm... sounds interesting. This might uhh explain why my computer totally crapped out when I was using a ocz ddr booster on my asrock 939dual sataII mobo (EVEN THOUGH I GOT TCCD) n i know they don't need a lotta vdimm, coughs but i tried anyway. And let it sit at 3.2v for a while while vcore was 1.4 and like everything got really really messed up in BIOS. the whole screen was like full of artifacts. And then i turned it off, reset the cmos, and the turned on the power, and my fans and hdd's n stuff started up for about a second and just shut down. I tried pressing the power button multiple times. but it didn't do squat. I was freaking out. So i took out the booster and and prayed nothing bad happened. And so far it seems ay okay. NEVER GONNA USE A BOOSTER EVER EVER AGAIN! (i mean it was my fault for using such high vdimm, but its ocz's fault that the voltage isn't stable, it keeps fluctuating all over the place from 3.2 to 2.4 to 2.8 to 4.2. Its ridiculous. I'm just glad that nothings broken. YET!

[tsuehpsyde]

Hmm, I had preached that high vDIMM killed CPUs after a # of processors were dying on the old BH-5 chips back in the 130nm days...I finally got some BH-UTT chips and Ozzimark told me about this as well as CCU, but I hadn't really seen the reasoning. I now understand a little better and I'll feel a little safer now when I go to rape this G.Skills.

[beta67]

First of all, the CPU doesn't have to do directly with the VDD, but with Vtt/Vref, wich should vary from 1.25 to 2V when you adjust the RAM from 2.5 to 4V. Maximum JEDEC Vdd voltage is 2.85V, and lowest voltage for A64 CPU's (CnQ activated) is 1.1V, so we know for sure that a difference of 0.325V between Vcore and Vtt is safe. This means that for a 1.35V Vcore voltage, we can have a safe Vdd of at least 3.35V, and for 1.5V Vcore -> 3.65V Vdd.
Probably the real danger is when those diodes go near the opening (conduction) voltage, wich should be ~0.6V for Si-based junction; if this is true, 1.35V Vcore and above 3.9V Vdd should kill the CPU instantly ... anyone wanna try ?

I agree with your logic Micutzu, but where did you learn the assumption that "the CPU doesn't have to do directly with the VDD, but with Vtt/Vref, wich should vary from 1.25 to 2V when you adjust the RAM from 2.5 to 4V"?
Particularly I ask because it doesnt sound so secure when you say "... which should vary ..."
Cheers!

[ozzimark]

not all boards supply the proper VTT


also, if we go based on the current (which should depend mostly on the square of the voltage), and 2.8v and 1.1v being the max differential, things look a bit different

vdimm     vcore 
 2.5     0.901 
 2.6     0.970 
 2.7     1.036 
 2.8     1.100 
 2.9     1.163 
 3.0     1.225 
 3.1     1.285 
 3.2     1.345 
 3.3     1.404 
 3.4     1.463 
 3.5     1.521 
 3.6     1.578 
 3.7     1.635 
 3.8     1.691 
 3.9     1.747 
 4.0     1.803

but who knows

[Micutzu]

I agree with your logic Micutzu, but where did you learn the assumption that "the CPU doesn't have to do directly with the VDD, but with Vtt/Vref, wich should vary from 1.25 to 2V when you adjust the RAM from 2.5 to 4V"?
Particularly I ask because it doesnt sound so secure when you say "... which should vary ..."
Cheers!

Vtt/Vref must always be half of Vdd, so at Vdd=2.5V Vtt/Vref=1.25V, Vdd=3V Vtt/Vref=1.5V and so on, at Vdd=4V Vtt/Vref=2V. Maybe that wasn't the best choice of words, replace "should" with "will" .

[MrSeanKon]

where can you measure vcore using a multimeter?

Some photos are here for general usage.
For more info download Guidemania.
I always bump Vcore too much and destroyed the IMC of my previous Venice.
Of course it was normal.

[flapane]

so no issues with my winchester a 0.97v and gskill@2.7?

[UnreaL]

Hey guys sorry to bump a dead thread but I just realised something.

The A64 OC guides need to all be changed so that people dont lower cpu multi and leave stock voltage while testing memory!

Thats probably one of the longest periods that this voltage difference occurs.

[Serge84]

This is questionable, I OCed my Sempron 64 2500+ E6 cpu with 1.4vcore and a 3.3v DIMM voltage in my hyper-X's and didn't do anything to my cpu. Hmm so now I got a venice DH-E6 but keep it at a super high voltage at 1.725v. Never had a prob like this with ever burning out a cpu. All or most CPU's can take about as much as a DFI can give it 2.1v. Some are crazy enough to run them that high. I'll run my TCC5 DDR600 OCZ's at 3.3v too. Only OCZ's arn't cheap. =P (seen them like upto 3.6v.) They can and love the volts like my cheap hyper x kingstons. So I guess I don't have to worry since I got my cpu running at high vcore with my DIMM.

[uOpt]

This is questionable, I OCed my Sempron 64 2500+ E6 cpu with 1.4vcore and a 3.3v DIMM voltage in my hyper-X's and didn't do anything to my cpu.

Uh, this thread says this should be fine, so no suprise here.

[[ITA]SEREUPIN80]

hello guys,

as you can read my configuration in my signature, i would like to have some advise from you about to set up my voltages on cpu and ram

thank you very much.

[deff_ins]

i like c'n'q+oc

i hope my system will be safe:
opteron 170 toledo watercooled
4x512 corsair tccd
dfi expert

cnq enabled
260x10 2.5-3-3-6 2T
idle 260x5 1.1vcore 2.9vdim
load 260x10 1.45vcore 2.9vdim

is it ok?

[mursaat]

To all that ask if their config is ok: go and do the maths guys:

Vdimm/2 - 0.325v = Min Safe Vcore

That's the most conservative formula on the full thread (well, the most is the one that implies the square of the voltage that ozzimark said, so simply check that post: http://www.xtremesystems.org/forums/...&postcount=115)

On a side note, and continuing with the OT: what happens with dual cores? I'm asking this because they refuse to oc with much volts (mine doesnt do 2650 with 1.45 but does with 1.375v).

Only the difference between VTT and Vcore counts? I think I read (sorry, I read the thread from beggining to reply and can't remember where) that bumping the volts help heating the cpu thus shielding it. Does that mean that heat also helps (advantage for DCs), or I have totally misunderstood (that point only )

[MadOverTolik]

1.) I still dont understand why is memory controller of E-stepping can be damaged using high VDIMM. Why are another, non built in, memory controller going not to be damaged?

2.) Where are protection diodes located? 100% not on MoBo (I checked DFI Lanparty)