L12 Mod Really Does Raise Fsb Up 20+ Mhz!!![Retired sticky]

[KnownKiller]

Try just using the one 3500 ofcourse.. Though if ya need the 512 then stick with the 2700.. Runing with 3 sticks in there is deffinitly going to limit your FSB.

 

[johan851]

Yeah, I'd agree with that. That much memory density leaves a lot of room for errors.

 

[tictac]

ok thanx dude... now i can boot at 235fsb but i have problem here... after 2-3minutes rime 95 my pc auto restart lho... dono which 1 not enough voltage

vdd = 2.1v
vdimm = 3.1v

 

[johan851]

well...you may have reached your limit. If it was me, I wouldn't be raising my voltage much beyond that....what kind of cooling do you have on your northbridge?

 

[tictac]

vantec iceberg4 on northbridge n abit stock northbridge cooler on southbridge... aero7 on top of mosfet

1 more thing if i up more vdd up to 2.2-2.3v can i cool it down with 80watt peltier? coz i afraid dat 80watt peltier cant handle the northbridge heat?

 

[johan851]

Like I said - you might've reached your limit completely. I don't know if extra cooling would help much...but I imagine an 80w peltier would do an ok job. Ask around in extreme cooling.

 

[[OC]This]

no L12, no BIOS flash, no vdd moddin' no nuthin.. the dud board right outta the box. This board sux...

 

[hitechjb1]

I come across this thread again since I was here in Aug 2003. Since then, I have some more results and ....


Here outlines some of difficuilities in overclocking this motherboard, though if over coming them, the NF7-S rev 2.0 has lots of overclocking potential.

At the end, there is a link to a lengthy post which discusses the various aspect of tricks
- bios version,
- multiplier,
- fsb_sense mod wire trick (or L12 mod)
- various bios settings, ...
to get it to work at high FSB and deliver high memory bandwidth efficiency.

But some of the boards (from my exeperience and others) require no special tweaking to get to 220 MHz +- 10 MHz FSB.

To overclock this board, first thing first, make sure chipset Vdd is 1.7 V, memory is PC3200/3500/3700 (preferably w/ windbond BH5/CH5 chips), Vdimm = 2.8 or 2.9 V.

From my experience overclocking two NF7-S rev 2.0, which has the best FSB potential, but some are very sensitive and require all kinds of trick to get it to work at high FSB.

- One failed mysteriously at multiplier 9, 9.5. 10 (hang, crash), could only do 215 MHz FSB. But with the right bios (version 10 only which is not recommended due to bios corruption), FSB_sense 166 mod, CPU interface enable, it can do 230 FSB with memory efficiency at around 95%.

- Another one can do 225 MHz without any trick and mod and bios change. But nothing can help it to go higher (limited by memroy controller in NB). Even with this one, there are problems with multiplier <= 10, memory efficiency suffers by 5-7%.
I only need mulitplier 11 or 11.5, since my CPU's can run 225 x 11 or 225 x 11.5, so multiplier 10 is not a problem for me.

Even you think your bios can handle multiplier 10 or under, I think better check the memory efficiency. It should be around 95% for this motherboard w/ CPU interface enable. If you get memory efficiency of only 89%, it is equivalent to losing 12-15 MHz FSB.


For details about the testing, effect of various bios version, bios setting, FSB_sense mod, memory efficiency, ...., click this link:
Summary on overclocking the NF7-S rev 2.0 (with Tbred B 1700+ DLT3C and ...) (page 15)

 

[hitechjb1]

I found that the FSB overclocking of the NF7-S rev 2.0 is very tricky, and there is no single recipe would work for all, as detailed later (update from a previous post).

Recently I also tried disabling APIC in the bios, as some people reported that APIC would get higher FSB for the NF7-S rev 2.0. As you said, going from APIC enable to APIC disable would hang Winodws XP (SP1) reboot, and it requires reinstalling (repair) XP (SP1).

After reinstalling XP with APIC disable, I found that it does not help FSB going higher at all (not 1 MHz), so this adds another discrepancy to the list of items that may potentially improve FSB overclocking of this motherboard. I will going back to APIC enable for this board.

Summary on overclocking the NF7-S rev 2.0 (with Tbred B 1700+ DLT3C and ...)

From my experience on two NF7-S rev 2.0 boards and reading results of many posts, it seems to me that there is no definite combination (single recipe) in terms of the following

- bios version: 10, 14, 16, 18, ...
- L12 bridge mod or FSB_Sense 166/200 mod
- bios setting CPU Interface enable/disable
- APIC bios setting

to achieve highest FSB and memory bandwidth. It has to be tried on a board by board basis (w/ memory modules used) to achieve its max FSB potential, which averaged around 220 MHz, some lower at 210 MHz and some higher to 230 MHz, with stock chipset cooling, without chipset Vdd mod, using good 3200/3500 CAS2 memory with Vdimm at 2.8, 2.9 V if necessary.

I am going to list a number of situations, no clear trends:

1. As some reported, some boards can go to its highest FSB with bios version 14, 16, 18, ..., without the L12 and FSB_Sense 166/200 mod (in this situation the mod may help very very little, few MHz (1-3)).

2. As some reported, some boards may need the L12 or FSB_Sense 166/200 mod to get stable higher FSB, by as much as 10-15+ MHz.

I installed two boards, one board was help by the FSB_Sense 166 mod by 10-15+ MHz, but one board was not help at all.

3. As some reported, some boards may need to go back to bios 10 to achieve highest stable FSB. But bios 10 is without the bios fail-safe saving feature of bios 14 or higher. One could get bios corruption w/ bios 10 and need a bios recovery kit to recover.

I would avoid using bios 10 long term, due to the bios corruption issue, and running a system with an outdated bios.

4. The boards may also require faster CPU above 2.2 GHz to achieve high memory efficiency around 95%.

5. Further, some boards may have stability problem and cannot run at high FSB at certain CPU multipliers (above or below are fine, strange, seeems to be some timing issues in the board ??).

One board did not like multiplier 10 (system hang), higher and lower than 10 were fine. One board did poorly on memory efficiency with multiplier 9.5 and below.

6. As some reported, CPU Interface (bios setting) disable made a noticeable higher FSB, as much as 10-15+ MHz. But some can go to highest FSB with or without CPU Interface enabled. But CPU Interface disable has significant negative impact on memory bandwidth performance (6-8%, see below).

7. As some reported, disabling APIC (bios setting) would get higher FSB for the NF7-S rev 2.0. Going from APIC enable to APIC disable may hang Winodws XP reboot, and may require reinstallation (repair) XP, so be careful.

After reinstalling XP with APIC disabled, I found that it does not help higher FSB at all (not 1 MHz). I will going back to APIC enable for this board. So this adds another discrepency to the list.

...

It seems to me that the timing of the chipset memory controller, CPU FSB interface, memory modules as a whole making the FSB overclocking very tricky and needed to be done on a case by case basis, without a definite clear recipe.

I think there is an intrinsic limit on FSB based on the combined system timing of the above mentioned components. The board's FSB overclocking would max out at certain level of memory bandwidth (MB/s), regardless of the bios versions, L12 or FSB_Sense mod, CPU Interface, dual channel or single channel, and how well the settings are tweaked and means to achieve the max FSB.

Regardless of the FSB MHz, the number to watch is the effective measured memory bandwidth and memory efficiency, which determine the overall system performance (instead of just FSB MHz). I found that

CPU interface enable (fast decode) and dual channel, integer memory efficiency ~ 95 - 96%

CPU interface disable and dual channel, integer memory efficiency ~ 88-89%

For single channel, memory efficiency would drop by 2-3% but FSB may go few MHz higher, hence single channel and dual channel is roughly a wash on effective memory bandwidth.

Main emphasis for performance should be getting CPU interface enable to work. Since the 6-8% gain of memory efficiency (as described earlier) for memory bandwidth w/ CPU interface enable would be equivalent to 12-18 MHz at the level of 200 MHz FSB. A lower FSB with higher memory efficiency may be better than a higher FSB with lower memory efficiency for both memory bandwidth performance and stability (chipset, memory controller, memory, CPU FSB interface).

Memory bandwidth (MB/s) and memory efficiency can be obtained from the latest Sandra (MAX3) memory bandwidth test, or calculated by

memory_efficiency = measured_memory_bandwidth / (16 x FSB)


On APIC, APIC should be enabled in general, ...

I also tried disabling APIC in the bios, as some people reported that APIC would help getting higher FSB for the NF7-S rev 2.0 (which is a very tricky motherboard for getting high FSB, even it has the most potential for highest FSB, see my previous post earlier).

Going from APIC enable to APIC disable would hang Winodws XP (SP1) reboot, and it required reinstalling (repair) XP (SP1). After reinstalling XP with APIC disable, I found that it did NOT help higher FSB at all (not 1 MHz). Apparently, disabling APIC did not work for me.

I went back to APIC enable for this board, getting back to the old FSB of 227 MHz, with CPU interface enable, 95-96 % memory efficiency.

APIC (Advanced Programmable Interrupt Controller) enable is recommended for Win2K, WiinXP (won't work with DOS, Win95/98). APIC enable is a must for dual processors. Each processor's local APIC is linked with the APIC bus for handling I/O APIC IRQ.

Even for single processor system, it is recommended for it enabled since it gives more IRQ lines (up to 64 instead of 16 when APIC disabled), faster and better I/O and IRQ handling.

Some reference links on NF7-S rev 2.0 FSB overclocking:

There are two logical pins in the Tbred B/Barton CPU called FSB_Sense[0] and FSB_Sense[1] to tell the motherboard that the CPU is originally programmed for FSB 133, or 166, or 200. Details about this and how to alter such are described, for example, in this link. An alternative way to alter such FSB configuration is by physically altering the L12 bridge (I personally prefer the FSB_Sense wiring trick mod than physically opening (burning) or closing (painting) the bridge).

Since some ppl reported that by altering the preprogrammed FSB_Sense signals from 133 to 166/200 or vice versa, one could improve the FSB overclocking of ABIT NF7-S rev 2.0 substantially higher (10-15 MHz), that is why the FSB_Sense or L12 mods have been becoming popular. But there are also many found that such mod did not help much at all.

FSB_Sense mod to set Tbred B default FSB from 133 to 166 (page 12)
FSB_Sense mod to set Tbred B default FSB from 133 to 200 (page 12)


NF7-S rev 2.0 FSB_Sense 166 and 200 mod (from 133) test results (page 12)
NF7-S rev 2.0 FSB_Sense 166 and 200 mod (from 133) test results (part 2) (page 12)

TbredXP 1700 & Abit NF7 rev2.0 boards = Not Very Friendly

 

[[OC]This]

The board I'm running atm, is dud, hates my xp1700 tbred, but loves Barton in terms of FSB oc'ing. I know we've talked about this a long ago. Yes I agree with you on everything you said. utilizing L12 mod and BIOS flash make some good increase in FSB overclocking. I needed BIOS flash and L12 to get my xp1700 working at high FSBs quite well, but this lastest v2.0 board I got here is sh#t. Of course there are variations between the boards even though they are the same version. I really missed the old one though. They OC'ed quite nicely, but this one tops out at blazing 195~ 200FSB on with my xp1700. The Barton 2500+ I tried recently does mid 230s FSB in Game, stable, and tops out at 242 FSB which I've shown you in the pic above.

 

[BowerR64]

I have a question about this mod, im reading a few links and on a few other forums there are 2 things to do to these chips, one is the "8bit" mod then the L12 mod.

WHen i look at my 1800+ i just got from newegg, i think im seeing the 8bit mod already bridged from the factory.

anyone else have a 1800+ can varify this?

here is the bridges on my chip

 

[johan851]

What does the 8-bit mod do anyway?

 

[BowerR64]

isnt it suposed to trick the bios into thinking its a barton?

One guy bridged the 2 on a 1700+ and he said it posted at "3200" and user define. Those are the only speed options he had after both bridge mods.

It looks like this new one i just got week 33, has the 8bit bridge closed.

 

[tictac]

after i flash my bios to modded bios 10... highest fsb i can get 242MHz

vcore = 1.93v
vdd = 2.1v
Vdimm= 3.1v

L12mod -> 166MHz....rocks

 

[johan851]

7mhz increase for you, right? Is it stable at 242?

Gonna have to try that 10 BIOS myself...hmm.

 

[ocerguy]

want to know if this mod will work on my 1.2 board and do anything worth a crap? thanks

 

[johan851]

I'm not sure...I think one of the sites says that it's specifically for the Rev2, but you could poke around a little.

What's your current FSB and processor?

 

[ocerguy]

johan I am using a 266 FSB XP2400+, right now I am at 171x12.5 but i have been stable to 195x11.5. kind of need better cooling system to get more but that is going to be finished next week so I am ready to do what I can to maximize my setup

 

[johan851]

Alright - try this link.
http://www.geocities.com/trats102002/nf7sFsbsense.html

It says it's for the Rev2...so if you don't have a Rev 2 use it at your own risk. However...the modification is really to the CPU, not the motherboard, so there shouldn't be a problem.

 

[tictac]

erk..... need help here....

i already done l12 mod to 166MHz

but when i upgrade my bios to bios 20...

in bios option when i clear my cmos my default fsb is 200MHz.... woooo wat is happening here... HELP!