AMD Turion 64 X2 Running on only one core!

I recently picked up an HP Pavilion Dv6812NR that is out of warranty but barely used. It wasn't working when I got it (neither windows or OS installation CD would boot completely.)

I tested the hard drives and RAM and all were fine, however the CPU tests on Ulitmate Boot CD wouldn't run, saying "idle sync timeout."

I tried everything, and during my research happened to read about someone with the exact same symptoms getting Windows to install by changing the HAL during windows setup (by pressing F5).

Just to see what happened, I tried selecting "ACPI Uniprocessor PC" HAL instead of multiprocessor, and to my surprise XP finally installed correctly.

Now I have this machine up and running, all drivers installed and it's perfectly stable. The Computer is in fact reported as ACPI multiprocessor PC in device manager. However in Task manager only one CPU graph is shown.

I then tried updating the driver for "computer" in Device manager, and selecting "ACPI multiprocessor PC". (This is meant to work if you installed Windows with an incorrect HAL). However, as soon as I restart after this The PC will not boot up, and Windows needs to be repaired / reinstalled. I have tried everything, and the ONLY way to install Windows on this PC, is with the ACPI Uniprocessor HAL.


So, It's definitely a hardware issue. I thought about replacing the CPU, but I'm concerned that that will be quite expensive and/or fiddly, and isn't guaranteed to be the source of the problem. Isn't it perfectly possible that I'd replace the CPU, only to find that the problem was in fact the with the mobo?

At first I was ready to get rid of this machine if I couldn't get XP to install properly, but now I've been using it for a few days , installed lots of programs and it seems to be running just fine. It seems as though one core of the CPU just isn't doing anything, but I still reckon this system feels faster than my P4 based desktop.

The main thing that I wanted to check opinions on, is whether there's any reason to mistrust the stabilty of this setup? Is there any reason to think that this machine won't continue to run fine like this, albeit in it's handicapped state. And if anyone could be kind enough to give a brief rundown comparison of what performance to expect from this "single core" 2.0ghz AMD 64, vs an AMD 64 running on two cores like it's supposed to, vs an older P4 3.0Ghz that would be amazing!


Thanks for any advice!

 

I could be wrong, but don't you need to install the dual core optimizer (available on AMD's website)?
Also, performance-wise, even the crippled AMD (don't know the model) will destroy the P4, but will be 10-15% IIRC behind the C2D of the same speed.

 

Have you tried this!

http://forum.notebookreview.com/showthread.php?t=60416

 

Thanks for the suggestions guys.

I have AMD dual core optimizer installed - but it just reports that "even though you have a dual core CPU the OS can only see one core"

As for the hotfix, that was included in SP3 which I installed before trying to update the HAL through device manager. No luck.


notyou, Could you explain a bit more what you meant with your speed comparisons? Did you mean that even operating on only one core my CPU (AMD Turion 64 X2 TL-60 ) would be way faster than a P4, but 10-15 % slower than a normal C2D? Or 10 to 15% slower than a similarly crippled C2D?

Also, any reason to doubt the long term health of my sytem if i keep it as is?

Thanks so much

 

10-15% slower than a similarly crippled C2D, but yes, much faster than a P4.
IIRC, I did a test with my old T5450 using SuperPI. It, at 1.66GHz would have been equivalent to a 4.8GHz P4 (remember, that's a single core of my previous C2D single SP isn't multithreaded).
I wouldn't worry about it, you could check the BIOS to see if the core has been disabled (I know I can do that on mine, weird, I know) or see if there's any warranty left, in which case you could get a replacement CPU.

EDIT: you may also want to try another OS to see if it's just XP.
Might I recommend an Ubuntu liveCD (don't actually need to install)

 

Sadly, HP's bios hardly lets me change anything

So how would the performance compare to the same CPU running properly on both cores. Is it the case that the main difference would really be multitasking, as XP would pretty much use one core per task anyway?

No there's no warranty left. If it's been working fine like this for best part of a month now no reason to think it should be less reliable than any other machine is there? Have you come across this happening to CPUs before?

If i knew 100% that it was solely a CPU issue I'd probably pay to replace it. However I'd hate to spend the money and then find out that it was actually a mobo problem or something else.

Thanks again for all your advice

 

That's why I suggested using the CD, it's relatively quick to download and burn to a CD to boot off of. If it doesn't see the second core, then we know it's a CPU problem.