Frequently asked questions

theme: Desktop Athlon XP Multiplier Adjustments on the fly from Windows

31th December FAQ:

Q: I do not understand your article, could you please explain to me how...
A: For starters: This article is about software controlled multiplier change. What you set in BIOS is hardware controlled multiplier change and it has nothing to do with this - software controlled doesn't depend on whether your motherboard is able to change multiplier in BIOS or (via DIP switches), whether you use wire tricks or not. Hardware controlled change works only at startup, software controlled works anytime, even from Windows. Software controlled is pure internal change inside the processor itself. No pins are affected by this. But for software controlled change there are some requirements that has to be met. First the processor must have some MSR registers enabled and those registers are disabled for desktop parts. You have to use regular mobile CPU or to modify your desktop part to mobile. To do this, connect one bridge on L5 on processor package. It is the second from right on Thoroughbred and Barton cores, the second from left on Palomino and Morgan cores. Second, chipset on your motherboard has to support software controlled change (eg. support PowerNow!) and the chipset has to be configured properly by BIOS. If your chipset doesn't support PowerNow!, there is no change it will work. If it does support it but is badly configured, then you have to adjust chipset settings by a program called WPCREDIT. On majority of motherboards however, this is not necessary.

Q: I heard L6 bridges change multiplier on mobile CPUs.
A: Wrong. L6 bridges define maximum multiplier you can set by software change. It is a upper limit multiplier, the highest value any software can force your CPU to transition to.

Q: When I click on "Set" button to change multiplier, system freezes or restarts.
A: This is because your chipset doesn't support PowerNow! or it is badly configured. In second case, some WPCREDIT changes will be required.

Q: Will this work on nForce 2 motherboards?
A: We don't know yet. There were some reports it does work on nForce 2 but majority of people say it doesn't. Especially Abit NF7 users complain it freezes system. Maybe some WPCREDIT changes will help us. Now I can say it doesn't work on nForce 2 and maybe it will with some luck.

Q: Your program doesn't work for me. Screenshot from CPUMSR looks like this:

A: This means you didn't turned your CPU into mobile one. On this screenshot see Frequency adjustments: Not Supported. This happens when L5 bridge is not connected or is not connected good enough. In order to enable missing MSR registers, you have to see here Supported. That however, doesn't mean it will work on your system - chipset has to support software controlled change.

Q: CPUMSR tells voltage is 2.00V. But it isn't !
A: The program will just tell you what processor requires through SoftVID pins. If your motherboard has SoftVID pins connected then motherboard should be running at that voltage. If not then this info is of no use for you.

Q: I am using Windows 98 and multiplier change doesn't work. But in Windows 2000 / XP it does.
A: I am aware of this problem. I am trying to find reason why it is not working on Windows 98. But I do not have Windows 98 what makes this task little difficult.

Q: Will it be possible for motherboard manufacturers to implement software controlled change into BIOS?
A: Sure. It would be quite easy since some motherboards do already do software controlled change to set maximum (L6) multiplier when they detect mobile CPU (that is why some motherboards loads OS at L6 settings - if they do, then BIOS used software change immediately after initialization).


29th and 30th December FAQ:

Q: I can't change voltage, why?
A: Voltage set by software is signaled to SoftVID pins that are different from VID pins. VID pins are used as startup voltage (or just voltage on desktop parts). Required motherboard circuits for VID are implemented on all systems but as for SoftVID they are usually present only on mobile systems. So when you change voltage by software, Lo (no voltage) / Hi (voltage) status changes at SoftVID pins. But because those are not connected on desktop motherboards to voltage regulator, nothing happens.

Q: Which of Athlon (K7) class processor cores can support on-the-fly multiplier adjustments?
A: Palomino, Morgan, Thoroughbred, Barton and also Applebred and Thorton (those last two are just Thoroughbred / Barton with disabled part of L2 cache).

Q: How can I turn my Athlon XP / MP on Palomino core (Model 6 - CPUID 066x) or Duron on Morgan core (Model 7 - CPUID 067x) to mobile one?
A: Just connect the second bridge from dot on L5 (located near L8 and L11):

Q: What do L6 bridges do?
A: They set maximum multiplier that can be chosen by software. When setting multiplier by software processor checks whether required multiplier is not higher than L6 settings. If it is, it sets L6 settings instead. By adjusting L6 settings you can set this maximum as you want.

Q: What multiplier will the processor boot at?
A: In all cases, processor will start at L3 settings (startup multiplier). However, AMD wants notebook systems to load OS at maximum frequency, therefore BIOS on mobile systems is required to do software controlled transition to highest multiplier (that is to do P-State transition) immediately after initialization. On desktop systems, there can be two scenarios. The first one is that the BIOS does not do P-State transition. In that case processor will load OS at L3 settings. The second scenario is that BIOS program is somewhat "mobile-like" and it will transition CPU to maximum multiplier - that is to L6 settings. This this second scenario you can't just cut all L6 (that would give you 24x multiplier) but instead you have to cut L6 to a multiplier your CPU can handle at startup.

Q: What voltage will the processor boot at?
A: If your motherboard doesn't have SoftVID pins connected, it will boot at VID settings (that is L11 settings). If it has SoftVID pins connected, then the answer is the same as for multiplier.

Q: Will this work for "super locked" CPUs (processors produced after 39th week of 2003)?
A: Probably not because those processors do not seem to depend on bridges at all. Moding L3 bridges had no effect for those so I do not expect moding L5 would. But maybe...
Some people say it works for those also and after changing them to mobile they are able to change multiplier by software! This was confirmed by many people now (as of 31th December).

Q: Will you make a utility like PowerNow! driver that would lower multiplier at idle and  return it to maximum under full load?
A: Yes! I have an idea how could this work and we will make such a utility. It is just only a question of time.


Petr Koc