voltages. vRAM higher than set in BIOS

rangor gubbins · 10 May 2008 at 14:50

I'm using an MSI P35 Neo2 FR with an E2200, and 2x 1GB GeIL ULL PC6400
In the BIOS (version 1.8 - the latest) i'm given loads of voltage options i've not seen before (just come from an Abit NF7-S v2.0 with an AMD Barton - old school i know).
I know the usual stuff: vCore, vRAM, NB v, but what is VTT FSB voltage, SB I/0 power, SB core power, and do i need to do much to them when overclocking?

I found this semi-useful info pack from MSI: http://www.msicomputer.com/msiforms2/maxP35.asp
which kind of explains what each setting does and recommended voltages to use, but i would like to hear any advice from anyone here too.

The reason I ask is that my RAM voltage is overly high regardless of what I set it too. In the BIOS i've set it to a range of voltages 1.95 - 2.10, but in Windows Speedfan always records the RAM v as much high (normally around 2.3+) which I think is a little high for this RAM (as well as unnecessary).

rangor gubbins · 10 May 2008 at 18:08

Ok, after a bit more tinkering it seems that the actual RAM v. is somehow linked to the CPU voltage. So, no matter what i set the RAM voltage to in the BIOS it doesn't change the actual RAM voltage (this is assuming Speedfan is showing the correct voltage). At 1.45v for the CPU, my RAM voltage goes up to 2.37v no matter what I try to set the RAM voltage to. Very weird. ~2.37v for RAM seems dangerously high to me.

Anyone else seen this before?

colmor · 25 May 2008 at 03:29

I have this same MB, with an E8400, and speefan reports the same thing for me. Only way to increase ram voltage is to increase CPU voltage. RAM is at 1:1 clock ratio right now, which results in under-clocked ram (733 mhz vs 800). CPU is at 1.3v and RAM (2.2 volt rated) is at 2.13. RAM will not run at spec at this lower voltage. Only way to get the RAM to 2.2v is to over-volt the CPU dangerously higher, which I do not want or need to do. Bios Ver 1.8. Find out anything more on this? What other apps are there to report voltages?

Cob · 25 May 2008 at 10:13

Sounds like dodgy boards. No way should the vcore and vdimm be linked.

And -

VTT FSB voltage - Helps get higher FSB. Shouldn't really need to be fiddled with much with the high-multipliered E2200.

SB I/0 power - Southbridge PCI-E voltage. Again shouldn't need to be fiddled with, but it wouldn't hurt to add 0.05v to it.

SB core power - Southbridge voltage. Again just set to 0.05v above the lowest setting.

rangor gubbins · 26 May 2008 at 22:03

hi cob, thanks for the reply.
I think (hope) the board is ok, as my RAM hasn't blown up yet and i found someone else on the MSI forum with the same problem. Some knowledgeable guy over there reckons its software mis-reading the volatages rather than bad voltages. For some annoying reason there doesn't seem to be a BIOS reading for vdimm.

When i get a bit of time I shall have a fiddle with those voltages and see if i can a better OC. Lapped my HSF and IHS today. Took ******' ages and doesn't seem to have made any difference in temp yet

colmor · 28 May 2008 at 02:39

gubbins-

I would like to think this, but I have dome some simple testing that seems to confirm the voltage reported by speedfan for the memory voltages might be correct. example:
CPU voltage reported at 1.3v (for a E4800 this is a bit overvolted), which results in the ram volts at 2.1v. With this setting I can clock my ram to 760mhz and still pass Orthos memory test. CPU passes Orthos CPU test.
But if I down the CPU voltage a couple of notches so that ram volts goes to 2.0v. With this setting my ram will fail the Orthos RAM test. The CPU will still pass the tests tho.

I have tried changing the ram voltage in BIOS but it seems to have no affect on the pass/fail of the ram testing in Orthos.

The only thing I can think of is this points to the ram voltage physically being affected in relation to the CPU voltage by a ratio of 1:1.625. One other test I need to do is change the ram speed ratio to see if it affects this voltage ratio any.

I too would like to know of another hardware monitor software to get a "second opinion".

rangor gubbins · 28 May 2008 at 09:02

hmmm, this is indeed worrying.
I will try running Memtest and see if it shows voltage (i have a feeling it doesn't though). Don't think i have anything else installed at the moment that will show vdimm (neither Everest nor CPU-Z show it).

rangor gubbins · 29 May 2008 at 22:52

@ Colmor - i can't get the MSI dual core centre to work (even after upgrading my NET framework to 3.5). HWmonitor doesn't show vRAM, neither does memset. Can't find anything else at the moment that might show vRAM. So basically i'm none the wiser. but i did have the side off my case today, and i had a feel of my RAM (ooo errr

), and its not hot. warm, but not hot. might not mean much though as i think iwas running the CPU test (small FFTs) rather than a RAM test.

Speedfan reads my vRAM at 2.35-2.4v. Surely my RAM would have died long ago with this many volts if its a real reading.