Athlon XP-M changing multiplier in the BIOS won't work

Link19 · Post by **Link19** » Mon Dec 13, 2004 11:17 am

I have a socket A Athlon XP-M 1900 CPU. When I try and change the multiplier in the BIOS, it doesn't change the CPU clock speed like it should. I thought all mobile Athlon CPUs were unlocked? What could the problem be? There is a set of switches on my motherboard that allows you to set the CPU FSB speed. The choices are auto detect, 133MHz, 100MHz, 166MHz, and 200MHz. You can also change this option in the BIOS. If you set it to auto detect, the minimum FSB speed you can select in the BIOS is 133MHz. If you set it to 100MHz, the minimum FSB speed in the BIOS is 100MHz, although you can still set it as high as 233MHz in the BIOS. Just seems odd that there would be a DIP switch for setting the CPU frequency when you can do it in the BIOS already. No matter what I've tried setting it on, the multiplier setting in the BIOS is not changing the CPU speed???? Any ideas as to why this is happening with a mobile Athlon XP.

Pjotor · Post by **Pjotor** » Mon Dec 13, 2004 11:44 am

Post a link to the manual, and we might be able to help you... Without any info on the brand, the BIOS, or other stuff, it's hard to give constructive advice.

Link19 · Post by **Link19** » Mon Dec 13, 2004 11:54 am

[quote="Pjotor"]Post a link to the manual, and we might be able to help you... Without any info on the brand, the BIOS, or other stuff, it's hard to give constructive advice.[/quote]

The motherboard is a Soltek SL-75MIV2-L with a VIA KM400 chipset. I can't post the link to the manual because the site http://www.soltek.com.tw/ is not working right now. However, the manual does not tell you much about what to do. The manual online is the same as the manual that came with the motherboard. I specifically got this board because I wanted a micro ATX motherboard that undervolted and this was the only one that was gauranteed according to what I've read at SPCR to have the option of undervolting the CPU VCORE to 1.1V. It is just making me angry that I go out and buy a mobile Athlon CPU (because they're unlocked) and a motherboard that has the features to adjust the multiplier and undervolt, but adjusting the multiplier won't change the CPU internal clock speed. I mean the BIOS has the option to change the multiplier from 5-18, and it will save the changes in the BIOS, but no matter what I set it to, the default multiplier of the CPU won't change even though it's a mobile Athlon, thus supposed to be unlocked???? Just irritating me!!!!!

greeef · Post by **greeef** » Tue Dec 14, 2004 7:43 am

Have you tried setting it above or below 12.5?

Some motherboards can only access either the 5-12 mutlitplier ranger, or the 12.5-18 range and need to be switched between the two, either with a jumper or a wire in the cpu socket.

See if either range is accessible.

griff

Link19 · Post by **Link19** » Tue Dec 14, 2004 10:34 am

[quote="greeef"]Have you tried setting it above or below 12.5?

Some motherboards can only access either the 5-12 mutlitplier ranger, or the 12.5-18 range and need to be switched between the two, either with a jumper or a wire in the cpu socket.

See if either range is accessible.

griff[/quote]

I believe the CPU has a default multiplier of 12, and the highest I tried is 12.5, but it made no difference either.

Chang · Post by **Chang** » Tue Dec 14, 2004 2:02 pm

Assuming it's a "normal" 1900 XP-M, it should top out at a 12x multiplier. However since mobiles are unlocked, the typical behaviour when dropped into desktops is to set it to the lowest multiplier -- 6x or so.

What multiplier is it stuck on?

Are you sure it's a mobile chip? Does CPUID identify it as a mobile? Does the OPN on the chip read AXMD1900xxQ3C?

Finally, did you write down the stepping / do you have the week of manufacture?

Jan Kivar · Post by **Jan Kivar** » Fri Dec 17, 2004 8:22 am

Try if You can change the multiplier with CrystalCPUID.
(PS. Don't get confused, the thread speaks mostly about A64s, but it should also support some Socket A motherboards)

Cheers,

Jan

Link19 · Post by **Link19** » Fri Dec 17, 2004 6:08 pm

Jan Kivar wrote:Try if You can change the multiplier with CrystalCPUID.
(PS. Don't get confused, the thread speaks mostly about A64s, but it should also support some Socket A motherboards)

Cheers,

Jan

That won't work for me. I have to be able to change the multiplier at the hardware level or in the BIOS. I am going to run an embedded Lnux on a CF card on this machine.

Jan Kivar · Post by **Jan Kivar** » Mon Dec 20, 2004 7:26 am

Link19 wrote:That won't work for me. I have to be able to change the multiplier at the hardware level or in the BIOS. I am going to run an embedded Lnux on a CF card on this machine.

Hmm... How about CPUFreq then, and/or cpufreqd? CPUFreq is included in kernel 2.6, but unsupported backports to 2.4 are reported. (hope I got all the terms right?)

Cheers,

Jan

roo · Post by **roo** » Tue Dec 21, 2004 1:42 pm

here are the manuals:
http://www.soltek.de/soltek/download/do ... L-75MIV2-L

JorgenGr · Post by **JorgenGr** » Thu Dec 23, 2004 4:08 am

Hi

I also have this Soltek MB. It's running with at xp-m CPU (2600+ I think).
O/S is linux. Vcore I have set at 1.125 and freq at 100MHz (=1500MHz, CPU temp 37C cel).
But it does not respond to change in multipyer.

You cannot use the xp-m PowerNow features on this MB, as it must be supported by the bios.
And you cannot change the mulitiplier in bios, mine is locked on 15x.

I think an ordinary Athlon allows change of multiplier by the MB.
But if that can be done from linux, i don't know.

Does anybody here know of a mATX socket A board, that support the XP-M in bios (Vcore min 1.1, multiplier 5 or less - and maybe the PowerNow functions) ??

Brgds Jorgen / Denmark

Tigr · Post by **Tigr** » Thu Dec 30, 2004 11:49 am

I had a long fight with Soltek about this since I also have this motherboard. Their response, in short, was that their motherboard allows changing the multiplier if the CPU supports it. When I pointed out that the CPU most definitely supports it, they refused to support me because I am using a mobile CPU in a desktop system. That's it. So I told them it was the last ever Soltek product I bought and we agreed on that

For the long version, see below.

Soltek support wrote: You can really set the multiplier in the bios when the cpu multiplier is
unlocked. There is a method that you can confirm it, please try to
change the cpu to another one. If it working fine without problem,
the multiplier of AMD Mobile XP 2600+ is locked.

Soltek support wrote: I have talked about the problem with our R&D department, they indicated
that the Athlon XP-M 2600+ has lower voltage consumption (1.45v), now
we can`t guarantee it works perfectly on the motherboard because the
kt600-rl only built with the circuits for the higher voltage consumption
of processor. For above mentioned, although the frequency of Athlon XP-M
2600+ is correctly recognizing in your motherboard, but it may still
fails in boot or became instable system or other problems happened such
as " the bios does not apply any changes for the multiplier settings ".
In other words, we have not tested it on the motherboard so we are not
sure without it runs with the motherboard fully.
PS, the processor is for notebook computer. Please link our website for
more information.

You get the picture. Do yourself a favour, get an Abit board, it works.

Petr · Post by **Petr** » Sun Jan 02, 2005 11:07 am

If the BIOS is AMI, then this is normal behavior as multiplier is set by PowerNow! transition to L6 bridges value. Until you change L6, you will have a max. multiplier, regardless of how you change startup L3 multiplier.

If the BIOS is AWARD, you must be one of those unlucky people who got locked chip (yes, there are very few locked Mobile Athlon XP-Ms). But you can still change the multiplier by PowerNow! transition through software, just make sure FID_Change command support is enabled in chipset's PCR.

JorgenGr · Post by **JorgenGr** » Sun Jan 02, 2005 3:55 pm

Hi
From the url
http://linuxreviews.org/howtos/power/At ... index.html
I found a reference to a small program that reduce the heat and power usage on many amd cpu's: http://www.nt.phys.kyushu-u.ac.jp/shimi ... nload.html
CPU temp on my PC (with the Soltek SL-75MIV2-L MB & XP-M cpu) dropped from 37-38 to arround 31C and watt usage from 65 to arround 57W.

Petr, can you give us some more information?
The bios i s from AMI. As I understand you, connecting the L6 bridge on the CPU will enable the multiplier settings in bios?
I assume, that PowerNow will still not function, as bios lack support for it.

Some programs access the hardware directly to set e.g. vcore and multiplier. But I have not found a version for linux.

Brgds Jorgen

Petr · Post by **Petr** » Mon Jan 03, 2005 1:41 am

For bridges meaning, read (the table) http://www.cpuheat.wz.cz/html/AXP_multi ... iplier.htm
AMI BIOS follows notebook guidelines and after start immediately switches to L6 value. AWARD doesn't do this.

That link you posted focuses on Stop Grant disconnect. This can not lower your full load power. It has a significant efect on idle power but at the expence of peripheral's performance (lowered HDD performance ect.) due to FSB reconnect latency - that can be somewhat speeded up by setting MSR to faster values.

JorgenGr · Post by **JorgenGr** » Mon Jan 03, 2005 1:42 pm

That is an interesting article Petr, thanks.

Now all I need a link to the linux version of the CPUMSR program

)

If I understand this correct, then when the CPU is an XP-M, it should be able to change multiplier and vcore, if the right registers are manipulated.

How do I get information about how to do this on a KM400A chipset?

Brgds Jorgen

Petr · Post by **Petr** » Mon Jan 03, 2005 2:54 pm

KM400A is KT400 like so it is reg. D5, bit 2 must be 1.

Voltage, however, can not be changed as there is no single desktop motherboard with SoftVID pins connected. You would have to make serious hardware changes to motherboard (soldering) to make it work. There was a guide in japanese how to do this.

JorgenGr · Post by **JorgenGr** » Tue Jan 04, 2005 1:20 pm

Hi Petr

Lets say I find out how to set reg. D5, e.g. with "setpci" - then what?
I still cannot cpumsr under linux.

Can I change the multiplier by setting a registry? (in the same way as enabling the multilplier with reg. D5)?

The Vcore can be set in bios, but I suppose you say that it cannot be changed by software.

Brgds Jorgen

Petr · Post by **Petr** » Tue Jan 04, 2005 2:38 pm

Multiplier is changed by Model Specific Registers access. As far as I know it is easier under Linux to access MSR than on Windows. Details, however, are hidden under NDA (Non-Disclosure Agreement) - I can't give you exact guide how to do that. You may find something in K8 BIOS Developer Guide available on AMD web site or in CrystalCPUID source code.