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

[squeakygeek]

If I were to do this on my 8rda+, would I still need to do the vtt (or is it vbt?) mod? I read that this prevents the mobo from dropping the vdimm under load, but since we aren't using the vdimm, but the direct 3.3v rail, it seems logical that I wouldn't need to, but I don't really know how these things work.

[STEvil]

might be worth doing... its more of a tracking issue as since vbt/vtt need to be 1/2 of vdimm.

[squeakygeek]

What exactly is vtt used for? could you maybe point me to an article or a good thread or something that provides an explaination? like why it needs to be 1/2 of vdimm? ect. thanks

[craig588]

I'm not quite sure, but I know that with it out of wack I only get ~220MHz out of BH5 that can do 247MHz with it proporly connected.

[squeakygeek]

Originally posted by craig588
I'm not quite sure, but I know that with it out of wack I only get ~220MHz out of BH5 that can do 247MHz with it proporly connected.

Running with a traditional vdimm mod, or with voltage direct to the memory, bypassing the vdimm?

[craig588]

Using a IC7 Max 3 using a normal style vdimm+vtt mod.

[squeakygeek]

What motherboardfaqs.com says about VBT:

The vbt has to be set to ensure that the system doesn't drop the vdimm voltage back to its factory setting when the system is under load. Read that last line again to make sure you've got it right. Without setting the vbt voltage properly, the system will not keep a stable vdimm voltage under load!

With this mod, we won't be using the vdimm. It's not like the psu's 3.3v rail is going to become unstable if you don't adjust the VBT. This leads me to believe that if you do this mod, you won't need to worry about the VBT mod.

What I'm looking for is educated or experienced insight that can tell me if my assumption is true or not. I don't know anything about the VBT other than what I quoted.

Is my quoted information correct?
Is my assumption correct that the VBT mod won't be needed?
Thanks

[craig588]

Thats VBT, we were talking about VTT.

[squeakygeek]

Originally posted by craig588
Thats VBT, we were talking about VTT.

Now I'm asking about VBT. Can someone tell me what the difference is between VBT and VTT?

[craig588]

yeah, your correct about not needing to do a VBT mod. In fact I dont remember ever doing a VBT mod on any of the mobos I have used.

I posted that previous comment because I thought you misread it. Sorry about that.

[squeakygeek]

Originally posted by craig588
yeah, your correct about not needing to do a VBT mod. In fact I dont remember ever doing a VBT mod on any of the mobos I have used.

I posted that previous comment because I thought you misread it. Sorry about that.

So what is VTT, how is it modded, why is it modded, is it also supposed to be 1.2 of vdimm? If you don't feel like explaining, a point in the right direction would be nice. Thanks.

[craig588]

I have no idea what it is, or why its supposed to be half of the Vdimm, but its modded because it gives a large overclocking drop if its not in sync.

Theres only one current board that doesnt track the VTT correctly, the IC7 Max3. Heres the VTT mod for it.

[squeakygeek]

Originally posted by craig588
I have no idea what it is, or why its supposed to be half of the Vdimm, but its modded because it gives a large overclocking drop if its not in sync.

Theres only one current board that doesnt track the VTT correctly, the IC7 Max3. Heres the VTT mod for it.

So I won't need to do a VTT mod on my 8rda+?

[craig588]

Probably not, but I have never used an Epox board, so dont quote me on that. Do a search and see if anything comes up.

[STEvil]

try just the vdimm, if it doesnt work well then unhook it until you get the vtt mod done also.

[Rio71]

vtt should (must) be the half of vdimm.
this is for termination of memory-bus (like scsi etc...)
with uncorrect vtt, stable speed is lower.

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

here the mod for ic7.
no lifting or cutting is needed... simply connect one of the grey wire... is enough and doing the "same" as one.
3 is for better distribution... high-end


second pic is my vtt-mod on ic7...

[enzoR]

whats that white foggy stuff on the pcb?

[Rio71]

its condensed kolophonium-fog (soldering flux) at flash.
i tryed with my digicam to make the tracers viewable.
... damn dark pcb. ... i like the simply (epox)green...

[GomerPyle]

Rio71 can this in theory be done on all mobos? Chaintech VNF3-250 or maybe the new Asus A8V if I post som pictures for you or some?

[STEvil]

as long as they dont have overvoltage protection it should be doable, even on some that do.

[Jalmir]

I was asking myself if that mod was more suitable for the RAM with the "TinyBGA" technology (more square chip) that support higher voltage and if the "TSOP" (the rectangular chip) was supporting that mush voltage.

As I have the second "technology" that "officialy" support no more then 2.8 or 2.9 volts, I wanted to know what type of memory chips was used, and if it is "safe" (those things are never safe anyway!) ...


Nice mod tho!

[GomerPyle]

Rio71 would love to have your knowledge in this area. To find the right pin, do I have to take the ohm-meter/multimeter and take the reader to dimm pin7 and ground to all the pins on the back. When I then find a 0ohm I have the spot to solder the 3.3v rail to.
Or am I missing something?

For ex.

[Rub87]

Some time ago I also did the vdimm=3.3v mod on my NF7-s.. with one 256mb dimm installed, vdimm nicely follows +3.3v and vref=vtt/vbt is 0.5*vdimm.. but when 2 big dimms (2*512mb) are used cdimm drops to 3.2v (in bios) while +3.3v is still 3.4 even under load!, you would think, 3.2v is still good but the problem is that vref=vtt/vbt follows the vdimm thats displayed in bios so with big dimms vtt/vgt drops below 1.6 while vdimm is actually 3.4 because its directly connected to +3.3v line...

What could be the cause of this? A to thin wire?

Do you guys think I could fix this by using a thicker wire to every dimm..?

Can't I directly put a wire from +3.3v to the point were bios reads the vdimm so bios would always see the correct vdimm..?

Or build some kind'a regulator that cuts the vdimm always exactly in half to suplly vref and vtt/vbt..?

sorry for my bad english

[Rub87]

Damn, forgot the pic:$

[Rio71]

jalmir, thanks.
i using here tsop winbond bh-5, bh-5 are bulletproof on 3,3v.
i have an bundle infineon 6-a with relabeled bh-5/6 and working perfect.