V Mod ABIT IX38 QUAD GT

[R*r]

what is the default vpll voltage?

my q66 show 1,65v increasing to 1,7v didnt effect to mac cpu fsb but total clock.want to use more but not sure couse never play with it before any one can help

usualy cant post n spi1m at 450x9 now can even though its not stable on 3d

increasing the vtt cant pump my max fsb also i think my chip is not good enough still max at 470.already reach 1,75v vtt

thanks for all the mod johnny time to look for better cooling

[zbogorgon]

Did a quick test this morning and the difference between my read point and your readings will be 0.3volts lower than mine, so you'll be suppling that 0.3volts more to the cpu than you think! I strongly urge you to reconsider your CPU VTT readpoint.

The CPU vcore mod will be up sometime tomorrow as I need to solder it on and test it, then take photos

maybe we have different boards then, in my case Bios/uGuru is showing lower value than DMM on this point (also without the mod) and if it would be 0.3V higher, than that means that motherboard is overvolting CPU VTT a lot over BIOS setting (at 1.5V selected bios shows 1.43, DMM shows 1.50)

[Brandybuck]

Everbody need vcore mod

[zbogorgon]

Everbody need vcore mod

FTW

[Johnny Bravo]

maybe we have different boards then, in my case Bios/uGuru is showing lower value than DMM on this point (also without the mod) and if it would be 0.3V higher, than that means that motherboard is overvolting CPU VTT a lot over BIOS setting (at 1.5V selected bios shows 1.43, DMM shows 1.50)

Difference can come from how the DMM interpretates the fast switching voltage. Best method is to solder to either the point I have shown or on the underside of the board to the inductor leg furtherest away from the MOSFETs. This will be a DC signal.

The board does overvolt on CPU VTT ion BIOS 1.6V -> 1.65volts measured at idle

[Johnny Bravo]

VCore Mod (Version 1)


OK I have figured out a way to control the vcore but it's not the most straight forward so while you all try this I will see if there is a more direct way.

OK first thing is to solder a 500ohm variable resistor in parallel with this resistor:



Now to increase the voltage you lower the resistance BUT this will NOT happen when tjhe CPU Core Voltage Offset is set to 0.0V.

It seems that this overrides the circuit that this mod work on so in order to to make use of this mod you want to maximise your offset voltage. So lets say you set 1.5volts vcore VID and then maximise the OFFSET VOLTAGE before adjusting the variable resistor.

[zbogorgon]

hurray, you'r the man

1.9v is selectable in bios so that is too much for most of common mortals, for other, max offset voltage is common sense

p.s. now you can start vmoding X48 board, we'll need all the mods we can get as soon as it's available

[Johnny Bravo]

Of course - looking forward to feedback on how far you guys can push the vcore and how well it copes. keep those Digital VRMs cool!!!

[Brandybuck]

Thx Johnny , I will try this vmod

[OverClocker_gr]

Hey johny,nice work there as always


Can you post a more clear pic of the points for the vpll mod?


Thanx


edit.

Ok...one of two pics wouldn't come up :p

[zbogorgon]

Did a quick test this morning and the difference between my read point and your readings will be 0.3volts lower than mine, so you'll be suppling that 0.3volts more to the cpu than you think! I strongly urge you to reconsider your CPU VTT readpoint.

The CPU vcore mod will be up sometime tomorrow as I need to solder it on and test it, then take photos

i did some testing about CPU VTT, bios setting 1.30V (btw 1.5V is max),
your reading point = 1.31V
BIOS/uGURU reading =1.31V
my (wrong) reading point =1.38V

when 50k trimmer is set to 9.7 Kohms it's +0.1V, when on 9.2 it's +0.3

[Johnny Bravo]

though you record your read point as going up rather than down as I did I'm not surprised as it depends on how your DMM "sees" the fast switching voltage off the MOSFET leg. However you can see that my measure point is more inline with what you would expect to see, plus as it's closer to the socket area it's a bit more accurate to what the cpu will actually get (avoiding any droop that could occur)

Your trimmer measurements do come as a bit more of a surprise, as I checked mine and got +0.1volt from 25Kohm but hey, if it works then it works!

[zbogorgon]

but hey, if it works then it works!

true

[Brandybuck]

I tried vcore mod but 1.92V max When I set lower resistance , not working Normally bios shows 1.86v and after mod shows 1.92v max

Vcore: 1.6v
VOffset: 0.3v max

[Johnny Bravo]

I tried vcore mod but 1.92V max When I set lower resistance , not working Normally bios shows 1.86v and after mod shows 1.92v max

Vcore: 1.6v
VOffset: 0.3v max

wait that doesn't make any sense, what is the maximum offset voltage you can select in the bios?

[Brandybuck]

wait that doesn't make any sense, what is the maximum offset voltage you can select in the bios?

Vcore : 1.6v
Offset: 0.3v max

ı give 0.3V max offset voltage
If you set 1.6v vcore , ı can give max offset voltage 0.3v

[Johnny Bravo]

no you misunderstand. THere are two ways to change the voltage in the uGuru BIOS for thw IX38 QuadGT.
Vcore goes up to 1.6 votls. hen underneath that there is an "offset" votlage which can go from 0.0 to 0.5/0.6volts.

Is this how your board is?

[Brandybuck]

no you misunderstand. THere are two ways to change the voltage in the uGuru BIOS for thw IX38 QuadGT.
Vcore goes up to 1.6 votls. hen underneath that there is an "offset" votlage which can go from 0.0 to 0.5/0.6volts.

Is this how your board is?

Johnny , yes I know normal settings 1.6v vcore max , 0.6v offset voltage max , but İf you set vcore 1.6V , Offset voltage can set max 0.3v (no 0.6v) . I set Vcore 1.6v and offset 0.3v and max 1.9v in bios or windows(uguru).

[Johnny Bravo]

rigth then try setting vcore to 1.3 volts and offset voltage to 0.6 volts then start to lower the voltage and see how far it can go up.

If this still doesnt wrok then there is a safely in place

[Brandybuck]

rigth then try setting vcore to 1.3 volts and offset voltage to 0.6 volts then start to lower the voltage and see how far it can go up.

If this still doesnt wrok then there is a safely in place

Hımm oke I will try tonight thx.

[Johnny Bravo]

edit that should read lower the resistance not lower the voltage!

[Brandybuck]

This vcore mod working very well but Abit mobo have Over voltage protection up to 1.95 - 1,96v

[Johnny Bravo]

OVP is gonna be hard to find without datasheet, but I'll see what I can do, don't think the abit engineers are gonna like me asking how to disable all their safety features

[jcool]

Especially when my boards died on me@1,4V max...

[zbogorgon]

any news on that OVP ?