"NF7 Vio-Vmem stabilization mod"
How to reach upper than 230Mhz on NF7(-S) rev2.0 ?
This thread is not supposed to be exact in all case , but i hope it will help some of you guys. I just want to share my experience like I did with the L12 mod , I only hope that this time nobody will burn me into flammes for being inovative
I don't know how to call this a mod, because it is not : but if it needs a name I would call it "NF7 Vio-Vmem stabilization mod"
Most of this thread is useless if you are already used to NF7 modding, go directly to NF7-S verification voltages
My specs:
ANtec True Power 430W 3.3V moded
XP1700+ 308 DLT3C that can do 2.55Ghz at 2.0V
NF7-S rev2 with Ultra-400 northbridge (week 0316) that would not do 230Mhz stable - Bios 1.0
2*512Mo OCZ PC3500-EL that can do 240Mhz at 3.10V
ATI sapphire 9500Pro
cooling : PGEO edenweiss cpu waterbloc, PGEO chipset bloc and PGEO graphic bloc.
1) Hard stuffs requiered :
[*]Voltmeter/Ohmeter[*]2 Kohms variator[*]2*10 Kohms variator[*]good northbridge cooling (watercooling or Zalman NB32J) [*]Zalman NB32J http://www.zalman.co.kr/english/product/nb32j.htm
[*]and finaly some good brand memory that could do the freqeuncy you aim at.
(I got 2*512 Mo OCZ PC3500-EL that will do little above 240Mhz still testing)
2) softwares requiered :
[*]Memtest-86 burnt onto a CDROM bootable : link[*]Prime95 : link
First of all thx for everyone that helped me for all the mods and teachings.
3) Context story :
After having some trouble with the 1st version of the NF7-S rev2.0 like 12V, 3.3V rails fluctuations, i deciced to vmod my Antec True Power 430W. This increadibly made me to reach 9*240Mhz stable. But i didn't know what i made to do it, so many mods in and so many hours of burning. ANd my aim was 10*240Mhz.
Then I made some thing wrong and all messed up : i had to RMA the board and to clean all the Vmod off. This is why this time, i made the minimum possible and pick out what wrong and what good.
4) NF7-S preparation
First of all, you must check the undervolting on the 5V , 12V and 3.3V rails.
Must always have all the more on full charge (like with Prime95):
-3.3>3.4v but we will see later why not 3.3v
-5v>4.9v
-12v>11.8v
If they are not stable, U will need to Vmod your PSU, just check on Xtream Vmods to get the one you need.
Ok, now you have a motherboard with great voltage, be sure that in next steps thats not your cpu that is holding you back.
Next step is little northbridge cooling : i had to lap a little to fix my watercool flatly.
Then take the Zalman NB32J and fix it on the southbridge.
Now, just do the Vdd and Vdimm mods as explain here with the 2* 10Kohms variators (i know it is said to use a 1 Kohm for Vdimm mod but use the 10 Kohm).
THe best bios for NF7-S is 1.0 for FSB maximum but there is a limit of 250 Mhz (later ones allow up to 300Mhz). You can flash your Mother board from windows with ABIT software tool : Abit Flashmenu, but make sure before you do that that Prime95 will pass more than 30 minutes without any errors (meaning your computer is stable enough to flash from windows)
5) NF7-S verification voltages
Now that you have a complete Vmoded NF7 with stable voltage, you will be able to boot the bios other 240Mhz with descent Vdimm and Vdd, if not make sure you have a 166Mhz cpu (barton or XP2600+) if you are like me with a XP1700+, just do the L12 mod. like that or that
We will begin to benchmark memtest98 from the bootable cdrom.
set the Vdd and Vdimm to what it need do boot and enter bios without any problem (for my part vdd=1.8V and Vdimm=3.1V)
Most important tests in memtest are the test#1 and test#5
test#1 errors : your timings are to tight
test#5 errors : your voltages are not stable
if memtest crash or freeze : Vdd is not enough
tip : to run test#5 without waiting test#2 through test#4 just type that at the end of test#1 : c + 2 + 5 + 5 + enter + 0
6) Most important of all this thread : the "NF7 Vio-Vmem stabilization mod"!
during test#5 (the most power hungry test) you need to check the effective vdimm and the High voltage on the mosfet near the Vdimm mod.
CONTRARY to most people state, VDIMM on NF7-S is directly dependant to 3.3v rail.
here a table :
3.3V-High voltage-Effective Vdimm
in bios 3.3V-3.35V-3.10V (i set with vdimm mod to 3.1V)
in memtest#5 3.3V-3.15V-3.04V (during test#5 and under full load in prime95 the Vdimm drops and errors appear)
"NF7 Vio-Vmem stabilization mod": Just up your 3.3V rail up to 3.4V or 3.5V depending on the reading of the High voltage Value
in bios : 3.45V-3.45V-3.10V (note that i didn't change the value of the 10K ohms variator)
in memtest#5 3.42V-3.29V-3.10V (at least vdimm is stable !!!!! and memtest#5 looping pass succesfully)
The rules that I state for this mod is :
don't go above 3.5V on 3.3V for safety.3.3V rail regules 'High Voltage' that should be 'Effective Vdimm+0.2V' otherwise, your Vdimm will fluctuate under full load and crash.
7) Pros and Cons :
At least you have a descent computer with descent speed- i'm joking right ? -
At least your memory that cost more than twice the Motherboard will reach its limits
But you void the PSU waranty
But your DDRAM modules will fry if you don't have a good air flow
But i lost a lot of time for modding for 10-15Mhz more LOL
8) warning
Be carefull you can fry any components of your computer with this mod : DDRAM, PSU, NF7 and use it at your own risk.
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