Multiplier on the fly

The following report is applicable the Athlon XP, Athlon XP-M and Sempron

This report is inapplicable to the Laptop as it is because of it which is written towards the motherboard for desktops. It is because processing of the bridge may have bad influence on operation of PowerNow! by the Laptop PC. However, description by my presumption is also included in it. Please confirm it for yourself.

The answer from us to the locked Athlon XP

The starting multiplier of the Athlon XP is fixed.

We recognized that Athlon XP's FID multiplier was Locked after about 39 weeks in 2003.
In these CPUs, it is proved that processing of L3 bridge is invalid. Furthermore, the multiplier changing function of a motherboard is not useful, either. But the cause is not clear. It is very glad that the multiplier of the Mobile Athlon XP-M is not locked.

Please watch the number in a red circle.

About this affair, we recommend you to refer to the following websites.
OCworkbench Unlocking a week 39 or later AMD CPU
CPUHeat & CPUMSR The Multiplier Adjustments on the fly...

And our answer is.

Multiplier change is possible by the software.

Although the Multiplier is unchangeable in the approach from hardware, it is possible to change it by software after startup. The software equipped with the function is as follows.
CrystalCPUID : Download from Crystal Dew World
Sample picture of Crystal CPUID (New window 20k)

CPUMSR : Download from CPUHeat & CPUMSR
Sample picture of CPUMSR (New window 24k)

In order to change the multiplier by such software, it must be recognized as Athlon XP-M.

Required specification
It is required that L5 [2] bridge should be closed. It is the same as mobile CPU exactly. And following one of chip sets should be used for the motherboard.
  • VIA : The product shipped after KT266A.
  • SiS : SiS735, SiS740, and SiS748.
  • ALi : We are not testing. Probably it can do.
  • ATI : It has succeeded in RADEON 320.
  • AMD : It seems that it is possible.
The following products are not supported.
  • nVidia : There is no success report.

About the maximum multiplier

The maximum multiplier which can be changed by such software is the following.
Athlon XP which closed L5 [2] : Since it is decided by L6, it is 11X.
Athlon XP-M : An original rated multiplier.

Changing the maximum multiplier

At last!! ..... We discovered that L5 [1] had an important function.
When L5 [1] bridge is closed, L6 bridge becomes invalid and the maximum multiplier is set to 24X.

This displays information with various CPUs by CrystalCPUID. Although explained later, please watch that "Multiplier / Max" is displayed as 24X in the following pictures.

But since priority is given to this setup of L5 [1] over L6 and it is going to start by 24X in the motherboard which starts in L6 multiplier when mobile CPU is used, cautions are required.

The Core voltage cannot be changed with a general mother board. It is only Laptop PC to be able to change the voltage.

The difference of operation by the BIOS vender.

According to a BIOS vender, it is necessary to consider how the bridge must be changed.

[ Type A ] The products are started by L3 multiplier, even when Mobile CPU is used.
At the Loked Athlon XP, it always starts in a rated multiplier also by the case of Mobile operation.
In these mother boards, it always starts by L3 multiplier or the fixed starting multiplier.
All are solved by closing L5 [1] and L5 [2].
According to our test, the BIOS vender applicable to it is Award.
[ Type B ] The products are started by L6 multiplier , when Mobile CPU is used.
Also by the case of the Loked Athlon, it can start by L6 by making it operate by Mobile.
At these motherboards, when L5 [2] is closed, it starts in L6 multiplier. Since it is going to start by 24X if you close L5 [1], cautions are required of these products. With the following products, change of the maximum multiplier is based on processing of the L6 bridge. And we recommend you for L5 [1] to leave as it is.
According to our test, the BIOS vender applicable to it is AMI.
[ Type F ] The product which is not supported
With these products, just as it is going to change a multiplier from software, it freezes. It seems that it is almost impossible. According to our test, it does not operate in the chip set of the nVidia.

Please refer to the list of next pages.

Reference, L5 : Operation mode of CPU

XP, MP, XP-M(Mobile) .... It is decided by this bridge to which product it will belong.
Therefore, it may be more suitable to call it "Product ID".

Please observe a setup of L5 [2] and L5 [1].

L5 [ 3 ] Closing : Multiprocessing Capable
L5 [ 2 ] Closing : Set to Mobile-mode
L5 [ 1 ] Closing : Canceling the value of L6, and set to 24x multiplier.
L5 [ 0 ] Closed : Maximum SVID by L8

If L5[0] is opened : Canceling the value of L8, and set to maximum.

AXDA2500DKV4D:::CAthlon XP 2500+,BartonDesktop
AMSN2800DUT4CC::CAthlon MP 2800+,BartonMultiprocessing Capable
SDA2400DUT3DC::CSempron 2400+,T-bredMultiprocessing Capable
AXMS1400FWS3BCC:CAthlon XP-M 1400+,T-bredMobile
AXMH2500FQQ4CCC:CAthlon XP-M 2500+,BartonMobile
ANXS1750FXC3SCC:CGeode NX 1750,T-bredMobile
AXDA2500DKV4D:C:CAthlon XP 2500+,Bartonpatched Mobile
AXDA2500DKV4D:CCCAthlon XP 2500+,Bartonpatched Mobile & multiplier 24X
AXDA2500DKV4DCCCCAthlon XP 2500+,Bartonpatched Mobile & multiplier 24X with Multiprocessing

In a surprising thing ..... It is that operation will be continued even if it changes the state of these bridges during operation of CPU. The changes and its reverse changes to Mobile from Desktop are also possible. These were checked by T-Bred1700+ on K7S5A. However, it is thought that it does not operate well depending on BIOS or a vender.

For closing the bridges

It is not necessarily required to scratch the bridge surface. We thought of "use of a cut end of the bridges."
I filled the laser pit, using conductive paint directly, without scratching the surface of the bridge. However, when it is not successful, we recommend you to scratch.

Reference, L6 : SFID for Mobile

L6 bridges are not used in CPU of the desktop version. They are all closed and value is 11x.
In the motherboard corresponding to mobile CPU, L6 bridge serves as multiplier rating.
Refer to the L6 bridges for PowerNow!.

5.0x 667 833CC:CC -
5.5x 733 917CC:C: -
6.0x 8001000CC::C -
6.5x 8671083CC::: -
7.0x 9331167C:CCC -
7.5x10001250C:CC: -
8.0x10671333C:C:C -
8.5x11331417C:C:: -
9.0x12001500C::CC -
9.5x12671583C::C: -
10.0x13331667C:::C -
10.5x14001750C:::: -
11.0x14671833CCCCCAll XP's
13.0x17332167:C:CC -
21.0x - - :C::: -
15.0x20002500::CCC -
22.0x - - ::CC: -
16.0x21332667::C:C -
16.5x22002750::C:: -
17.0x22672833:::CC -
18.0x24003000:::C: -
23.0x - - ::::C -
24.0x - - ::::: -
3.0x 400 500 :CCCC -
19.0x - - :CCC: -
4.0x 533 667 :CC:C -
20.0x - - :CC:: -

C = Closed , : = Open

Reference, L8 : SVID for Mobile

L8 bridges are not used for the Athlon of the desktop version. They are all closed.
In the Athlon of the mobile version (or mobile mode), L8 bridgs are the same setup as L11 bridges. Probably they should be used by PowerNow!.

This bridge is used as maximum of SVID recognized by software. The value of this SVID can be changed by software. But in the usual motherboard, it does not have the hardware which can use it. Therefore, even when SVID is changed, CORE voltage does not change at all. Of course in Laptop PC, it could be changed.

Appendix : About closing of the bridges for the locked Athlon

When you need processing of the bridges, be careful of below.

How to set the bridge of [Open] to [Close]
We know the Laser pit should be filled with an insulator before anything else. Then, it is made to [Close] by using electric conductive material.
In the new package(#27648), it might be difficult to connect two points in the bridge. In this case, it can be solved by filling the laser pit directly with the electric conductive material.
How to set the bridge of [Close] to [Open]
The bridge is set to [Open] by cutting carefully with an edged tool.
L bridgesMethod of closing the bridges for the locked Athlon XP
to GND
+ closing
L1It is connected from L3 to BP_FID pin.Insulated--Please maintain this state.
L2Level2 Cache controls1k OhmNon-recommendation
(see notes)
It may be invalid in the Locked Athlon.
notes : The behavior of the L2 Cache might be not correct.
L3Start up Multipliers1k OhmInvalidIt is also impossible to use the multiplier change function of the mother board.
L5Operation mode of CPU0 Ohm - OptimalSee : L5 Bridges
L6SFID, Rated Multiplier for Mobile0 Ohm - OptimalOnly in Mobile CPUs
L8SVID, Maximum Core voltage for Mobile0 Ohm - OptimalOnly in Mobile CPUs
L9It is connected from L2 to L2_control pinInsulatedUnnecessaryNo GoodIt may be invalid in the Locked Athlon.
There is no advantage usually.
L11VID, Startup Core voltage0 Ohm - OptimalSee : L11 Bridges
L12FSB auto-detection1k OhmBest
(see notes)
It may be invalid in the locked Duron
notes : It is unnecessary in a lot of mother boards.
See : L12 Bridges

[ - ]as not recommend

The function of L5 [2] and L5 [1] was solved with the help of the following. Thank you.
Hiroshi : He performed the difficult test of L5 [1].
Junkshop : He decoded the function of L5 [1] and L5 [2]. And I appreciate offer of a picture.
Furthermore... Many BBS members about Athlon in Japan.
The test became possible by CrystalCPUID and CPUMSR. I am thankful to these authors.
  • Updated on 08/01/2004
  • The mother board list was updated on 06/12/2004
  • The mother board list was updated on 04/05/2004
  • The mother board list was added on 03/15/2004
  • The mother board list was added on 02/10/2004
  • The answer from us to the locked Athlon 01/29/2004

Please solve the question to this report using your favorite discussion forum. I am because it may be unable to answer appropriately though I receive your mail, since English is weak.

Copyright 2004 ita. All rights reserved. Never reproduce or republicate without written permission.