Hello people.

I have an Athlon 64 3000+ socket 754, stock speed 2.00 GHz (200 MHz x 10), memory stock speed 200 MHz (DDR 400), running on an ABIT NF8 motherboard (NVIDIA nForce3 250Gb chipset). I have found through experimentation that the optimal overclock setting for this machine is 277 MHz x 9 = 2.49 GHz, setting memory in BIOS to DDR 333 speed (the effective memory speed will be 277 * 166 / 200 = 230 MHz).
I am running 64-bit Kubuntu 7.04 (Feisty) with kernel 2.6.21.5 compiled for this machine from the kernel.org archive sources. I am using powernow_k8 and would like to keep using it. However, even if I set the CPU's multiplier to 9x via the BIOS, powernow_k8 will change it to 10x, getting my CPU to 2.77 GHz and making it unstable. It overrides the BIOS, following a FID/VID table like this:

state 0: multiplier=5x, VCore=1.100 V
state 1: multiplier=8x, VCore=1.400 V
state 2: multiplier=10x, VCore=1.500 V

I installed the cpufrequtils package in hopes that it would be able to limit the maximum multiplier to set. It is, however, only among those values above, meaning I'd be stuck with a multiplier of 8x.

I dual-boot this machine with Windows Vista. In Windows I have a program called "RightMark CPU Clock Utility" (RMClock for short) which gives me access to all possible multiplier/voltage settings for my machine (same as BIOS). I can set multipliers from 4x to 10x (4x-5.5x, then 8x-10x, in steps of 0.5x), and core voltages from 0.800 V to 1.550 V in steps of 0.025 V. I disable Windows' CPU frequency control (it is too sensitive and CPU speed fluctuates a lot even under load) and hand it over to RMClock. With it I am able to customize the multiplier/voltage used for each CPU demand level, so I would be able to just set the maximum level to 9x multiplier and have it running the way I want. Is there a way to do what I describe here on Linux?

[Edit] I have found out from further testing that this FSB setting I mention causes some instability in my machine, so I had to back off. However I still would like to know if there is a way to do what I mention above. Thanks in advance.

I think I would try for the best 10xFSB speed you can get (10x249 perhaps) then once it goes into power saving and comes back out using the 10x setting you will have no problems. One thing I noticed when doing the same with my old AMD64 machine was once it went into the power saving and came back out a cat /proc/cpuinfo will tell you that you machine is running at its stock mhz but in reality it is still running overclocked just something to look out for if you see similar.

Yes, I know that. It's a "property" of kernels > 2.6.15. I can tell because even though /proc/cpuinfo states that it's still at stock clock frequency, the bogomips number increases and, for Athlon 64 machines it's always 2x the real clock.
I ended up going with FSB 248 x10 = 2.48 GHz. I think I'll try tweaking the memory timings/voltage to squeeze some more out of this machine then, since I'm stuck with a memory clock of 206 which is near stock - I can't run memory at 1:1 with the FSB with this setting because the Athlon 64's memory controller tops out at 230.

It is that way for pretty much anything as far as I can tell at least on any machine I ever looked it was always 2x.

I take it you mean for your chip? With my old X2 3800 I used to run 10x240 4xHyperTransport memory set at DDR400 so running it 1:1 at the 240 but I had DDR550 ram in it so maybe that made the difference getting the higher FSB.

Usually Abit motherboards set voltages a little lower than what the processor needs. I suggest increase the voltage until the computer is stable enough at a multiplier of 10.

The sysfs may have a few files that you can echo to change some settings. To make changing these settings make sure cpufreq utilities are installed. Also you can use either cpuspeedy, a simple client program to adjust frequency, or powernowd, that runs in the back ground to adjust the frequency depending on the load.

Until ACPI feature of the kernel advances further to allow changing the multiplier or voltages, you will have to stick with changing the frequency.

moderator please delete others.

Usually Abit motherboards set voltages a little lower than what the processor needs. I suggest increase the voltage until the computer is stable enough at a multiplier of 10.

The sysfs may have a few files that you can echo to change some settings. To make changing these settings make sure cpufreq utilities are installed. Also you can use either cpuspeedy, a simple client program to adjust frequency, or powernowd, that runs in the back ground to adjust the frequency depending on the load.

Until ACPI feature of the kernel advances further to allow changing the multiplier or voltages, you will have to stick with changing the frequency.

Usually Abit motherboards set voltages a little lower than what the processor needs. I suggest increase the voltage until the computer is stable enough at a multiplier of 10.

The sysfs may have a few files that you can echo to change some settings. To make changing these settings make sure cpufreq utilities are installed. Also you can use either cpuspeedy, a simple client program to adjust frequency, or powernowd, that runs in the back ground to adjust the frequency depending on the load.

Until ACPI feature of the kernel advances further to allow changing the multiplier or voltages, you will have to stick with changing the frequency.

Usually Abit motherboards set voltages a little lower than what the processor needs. I suggest increase the voltage until the computer is stable enough at a multiplier of 10.

The sysfs may have a few files that you can echo to change some settings. To make changing these settings make sure cpufreq utilities are installed. Also you can use either cpuspeedy, a simple client program to adjust frequency, or powernowd, that runs in the back ground to adjust the frequency depending on the load.

Until ACPI feature of the kernel advances further to allow changing the multiplier or voltages, you will have to stick with changing the frequency.

Yes, I've read an article about socket 754 Athlon 64 overclocking some time ago... the writer used a 3000+ just like mine, with high-quality RAM and also topped out at 230. So I guess it has to do with the memory controller - as far as I know it's internal to the Athlon 64 chip. I think S754 Athlon 64s don't really go higher than that - you mention you used a 3800+ Athlon 64 X2, I assume it's Socket 939 so it must have a different memory controller which will handle the higher frequency.

Yes, I see that's it then. The other option I have is disabling Cool'n'Quiet entirely from the BIOS, that way it'll enforce whatever I set in the BIOS. That's what later revisions of the BIOS on my motherboard do automatically (enabling the overclock control automatically disables Cool'n'Quiet), but I reverted the BIOS upgrade back to an earlier revision because I want to have control over that. Apart from saving energy Cool'n'Quiet will extend the life of the CPU, which will give me a bit more time until I upgrade, so it's always nice to have.

Well, thanks for all the responses and info.

All this talk about overclocking and I'm wondering for an extra 20-25% of speed at the risk of burning out your processor, is it really worth it??? With your 3d hardware accerating video card, what on earth do you need to overclock the processor for?

And while you at it, is a AMD 3000+ operating between 45-55C in the proper temperature range. It seems to be the case. The reason I'm asking is because the dropline gnome sensor applet keeps showing 47C and a temperature guage in RED. As opposed to brown or green (*when at lower temps like 30-45).

Just wondering if everything is *cool* at the medium 47-51C that my seems to be running at. Just wanna compare notes.

Thanks

- Perry

ps.
updated: according to my bios, overclocking will only give me between 1% - 10% of a possible enchancement... NOT worth burning out my AMD 3000+ over... thanks!

Encoding video, compiling software you know things that more MHZ make an actual difference in the time it takes to get it done.
50C is reasonable for a load temperature if your machine is running around there at idle then you should probably be looking at better cooling or making sure that you have the Cool'N'Quiet enabled in your BIOS and have installed the powernowd to be using it, with it running you should be in the 30's or low 40's at idle.

I did not want to say in previous post. I agree with perry.

I do not recommend overclocking because the reliability of the data is not as good as it should be. If I were compiling video, I just get a faster single core processor that is pre-tested to produce reliable data. If not in the business for your clients, screw with a faster processor and wait for the results.

Overclocking just creates bragging rights and unreliable data.

Question is.. how to use the thing?

i'm 1/2 afraid just to let it run by default, anybody know what to do ?

- perry