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I think I may have finally figured out the problem. Today I did some Memtesting, during which time I measured my 3.3V line on the VDIMM mosfet with a good Fluke DMM. Much to my surprise, under heavy load my 3.3V line drops to about 3.1V! That was the reason VTT was dropping when running memtest. (At least it was tracking properly :p:.)
So, to remedy the problem, I am going to do the PSU sense wire mod to the 3.3V line of my PSU to get the voltage a little higher. There may yet be hope.
I have a question. I want to voltmod my nf7-s with tictac's 4th method. I want to do all three mods. From what i understand the vdd will be half of ur vdimm, wich is the 3.3 rail -0.2 fluctuation. I have an OCZ powerstream 520 with the adjustable rails. So that means i should put the 3.3 rail to 4.0 to get 1.9 vdd?? That just doesn't seem right, so do you have to do an other mod in order to get a higher vdd voltage?
You're wrong with vdd
vdimm = 1/2 vtt
vdd is a north bridge's voltage
If you raise +3.3V rail to 4.0V, it will gain nothing, vtt will be equal to 1.45V
That's why vtt mods is needed, on Abit there's vtt's limitation (to 1.45V, you can
raise +3.3V to 4.0V, raise vdimm with VR to 3.2V, but vtt's maximum will be 1.45V,
until you will mod it)
Vtt = 1/2 Vdimm ;)Quote:
Originally Posted by Tonic
hmm, my vtt/vbt seems to track up to ~3.4. if i give any more vdimm, i get immediate errors. i have a newer board (blue slots). i know someone else with an older board, and they track as well (dont know up to what point though).
i havent verified the tracking with a dmm though...
just do 3.3=vdimm mod, VTT tracks fine then.
Very good idea to put cooling on the VTT IC anything above 3.1v though, it passes 60c quite easily...
Rub87, thanks, my error ^^
Ok I think i understand know. But what about the vtt=vref mod? Does this effect the vdd voltage whatsoever? Or do i need to do the regular vdd pencil mod in combination with the 3 mods described in the 4th method?
why do all that work?
vdd does not track vtt, vbt, or vdimm. vdd is chipset voltage and does not relate to ram voltage.
Yes i know, but i need a higher vdd voltage (1.9ish) For a higher fsb and higher clock speeds. But now i know none of the earlier mentioned mods effect the vdd voltage :) So i'll just do the pencil mod.