PSU's 3.3v Rail directly connected to/as vdimm

[Rio71]

Originally posted by HKPolice
Plz post update for IS7!!

hi,
on is7-e it worked perfektly, same like the others.
have done this mod few days after first post.
also nothing special here with this mod, but an vtt-mod (half vdimm) should needed (necessary).
is7-e running now as my main-rig for weeks with 4 x 256mb infineon 6-a.
sorry, i have not made some pix bevore mounted in my case.

[HKPolice]

Originally posted by Rio71
hi,
on is7-e it worked perfektly, same like the others.
have done this mod few days after first post.
also nothing special here with this mod, but an vtt-mod (half vdimm) should needed (necessary).
is7-e running now as my main-rig for weeks with 4 x 256mb infineon 6-a.
sorry, i have not made some pix bevore mounted in my case.

I tried the mod on my IS7, and the board won't boot anymore.. Doesn't post, no beep codes. I think the BIOS chip got screwed over.. cuz the symptoms are like when I had a bad flash from before... I removed the mod, and I can still measure voltage from VDD, VDIMM, VAGP and VTT... the fans spin, but nothing...

I am gonna get the bios chip hot flashed.

My 3.3v rail was 3.4v, but I doubt that matters. I removed everything from the board, and put it on an asus P4P800, and everything works... I know i soldered the right points because I measured pin7, and found the point on the back of the board..

[Rio71]

mmm... my worked perfektly.
can you post an pic from your board-backside with mod ?
is vtt moded ?

[HKPolice]

Originally posted by Rio71
mmm... my worked perfektly.
can you post an pic from your board-backside with mod ?
is vtt moded ?

Yes, i did all mods, VTT, vdimm, vagp, vdd, everything worked before. I undid the mod, waiting for a new bios chip

[Boyne7]

how does one go about finding out exactly what point on the back of the board u solder the 3.3v line to?

[Boyne7]

hey enzor, you said that you might try this mod but using the 5v line instead, how would you go about building a voltage regulator circuit like you mentioned that could adjust the voltage down to 3-4v from 5? also would this regulator be adjustable?

[Boyne7]

Could i just add a vr in series on the line to resist it down to the desired voltage? or am i missing some pertinent piece of information

[STEvil]

VR's are only rated at very small amounts of power, which means they would more likely catch fire if you did that.

You may be able to use a 25w or larger VR, but that may also get hot if more than 25w is used..

[mat3003]

Does v- theMod go also on the Asus P4c800-e?

If I connect the 3.3 LINE directly with the RAM, however the Northbridge gets unfortunately no more tension than default.

How do I make then the Vdd mod?

[Boyne7]

ah, that makes sense most vrs i see are only for 1.5watt or so. makes perfect sense that they would burn like that
thanx.

[Rio71]

[B]how does one go about finding out exactly what point on the back of the board u solder the 3.3v line to?

see first post pin7, count from pin1. take an very close view, "1" is printed on plastic !!
use an "continuity tester" (ohm-meter) and make sure se correct soldering point on backside have 0 ohm to pin7 (really up to 0.3 ohm).
the 3.3v rail ist the orange wire on atx-plug.


the regulation from 5v is not so easy.
you need an low-drop, but it is possibly not enough.
and the amperage ist rally high.

dont use a resistor. vdimm will high fluctuate and jumping.
high vdimm with less load, low vdimm with high load.

[enzoR]

Originally posted by Boyne7
hey enzor, you said that you might try this mod but using the 5v line instead, how would you go about building a voltage regulator circuit like you mentioned that could adjust the voltage down to 3-4v from 5? also would this regulator be adjustable?

FOR IC7-G:
(still experimental)
lift up source legs of vmem mosfets and put 5v to those so instead of the vmem coming from the 3.3v line it now comes from the 5v line. however i'm still trying to figure this out with hipro5 as apparently if the board is not powered on the vmem mosfet will get 3.3v from the 3.3v stand by line. it might require to lift up the whole mosfet(s) of the board and maybe a diode or 2 on the 5v line going to the mosfet to lower 5v a bit to something like 4v. if this mod would be a sucess it would mean we wouldnt have to be modding our 3.3v line for xtreme vmem anymore to like 3.8v. I'll keep you up-to-date.

[enzoR]

Originally posted by Rio71

the regulation from 5v is not so easy.
you need an low-drop, but it is possibly not enough.
and the amperage ist rally high.

dont use a resistor. vdimm will high fluctuate and jumping.
high vdimm with less load, low vdimm with high load.

yea its not easy.... what do u mean by a "low-drop"? do u mean something like what we are trying to do with the diodes to bring the 5v voltage lower? yea resistor sucks. hmm anyone feel like building a LM317T vreg for our mems?

[Rio71]

yes, diodes is the one possible and cheap trick.
and the various shottky or normal, any vdimm ar possibly.
... and the diode characteristic is good too, better than resistor.

but the current is matters.
estimated, a 256mb at 3,8v could up to 3 ampere, a 512mb up to 6 ampere.
... so high(er) current diodes is needed.


with "low-drop", i mean LM317 and derivates (for higher current) available as low-drop types.
the minimal input-output voltage differences is lower, near 1v.
normally is 2v-3v minimal.

[Rio71]

Originally posted by enzoR
FOR IC7-G:
(still experimental)
lift up source legs of vmem mosfets and put 5v to those so instead of the vmem coming from the 3.3v line it now comes from the 5v line. however i'm still trying to figure this out with hipro5 as apparently if the board is not powered on the vmem mosfet will get 3.3v from the 3.3v stand by line. it might require to lift up the whole mosfet(s) of the board and maybe a diode or 2 on the 5v line going to the mosfet to lower 5v a bit to something like 4v. if this mod would be a sucess it would mean we wouldnt have to be modding our 3.3v line for xtreme vmem anymore to like 3.8v. I'll keep you up-to-date.

i tryed weeks bevor an similar setup with the modded p4p800.
for experimantal, i lifted the mosfet-pin to vdimm.
i have thinkhing, now a vdimm- change in bios is needles.
but is not !
with an setup 2.4c 1:1 and 4 x 256mb for playing high memspeed.
bios vdimm settings to 2.55v and 2.85v.
with 2.85v i have an big improvement in runnig higer fsb.

[Rio71]

hi,
here an little but important update.
i have here an board with a switched dimm-vrm.
to do is additionally, lifting one leg of the coil (near dimm-slot) for making the mod working.


i trying this on epox 4pca3i rev2.0.
absolutely same switched-vrm should be on 4pca3+ and 4pca3x rev 1.x
the negative vrm-mosfet made the mod not working. when i press start, board go to on-off-on-off-on-off... (fast)
with lifting a coil-leg the switched vrm ist "off" for disturbing the 3,3v-to-dimm.
an vtt mod ist not needed here, rising "automatically" with vdimm.

interesting is, this board using the 5v rail for generating the vdimm.
without mod, older bios can set the vdimm up to 3,3v, with newer bios only up to 2,9v.
possibly, the dimm-vrm can't take easy high voltages on much ram, and epox have known this an disable. ???
so an common vdimm mod are possible for upping the vdimm, but could be killing the dimm-vrm fast.
but with 3,3v-to-dimm mod is no problem here........ only the psu or ram.



edit: typo "on" to "one"

[solo]

on the epox4pca3+ rev2.2 boards, we dont have one of those coil-leg things

i think i might just go ahead with the mod then.

anything else i have to do besides solder the 2 points togheter?

and on the vdimm solder point, do i just follow the pic you previously posted?

it looks liek its the 7th pin


EDIT:
went ahead with the mod: and everything works great

but i think i had some reset issues
further testing is needed

[EmineM]

could someone post a picture for this mod for the abit ic7 ?

[solo]

the ic7 mod should be done hipro's way
much easier/better

[pkrew]

Originally posted by Boyne7
could this mod be done on an a64 board so that you could run as much vdimm as you want (up to the max of the 3.3v line) to your ram without having to worry about frying the a64 cpu do to high vdimm voltage? if so this could be extremely handy to us a64 users

There's a mod very much like this for the ga-K8N.

[moparacer]

Ever figure out the reset issues Solo? Any chance you could post some pics or details of the 4PCA3+ mod here? I really need to try a mod on mine bad.... 2.9v on my mushkin 3500 BL2 just isnt cutting it.......

[ojdr2001]

Anyone knows the soldering points on a ASUS P4C800 for this mod? Vio direct to vdim.

Thanks in advance

[VoRtAn_MaDgE]

Estou tentado Orlando

[squeakygeek]

STEvil: please update on the 8rda+

[STEvil]

Never actually got around to doing it, but it will work.