To XP-M or not to XP-M?

[Jo The Veteran]

This just came up. I found an Athlon XP-M 2600+ with the Barton Core CPU in an add in a very sweet price. The guy who putted the add said it's compatible with desktop pcs also. I've tried to check with the AMD site but it's a big mess over there, only showing the cool new stuff they've got and burying older technology like this with useless info. I've also tried to check the site of my MotherBoard (chaintech) but it's also a mess. From the manual i know for SURE that THIS cpu "Athlon XP 2600+ (Barton)" IS compatible with my system and the XP-M may be the same socket (A) and all however i can't keep wondering. Can anyone tell me for sure?
(Photo from the CPU)

[mh2360]

The XP-M 2600+ Barton has 133mhz bus speed and the XP 2600+ Barton has 166mhz. You really need to check your motherboard, what make/model is it?

[ahhaa]

if you google a part Make&Model, and add the word review, you usually get pretty good info

[Jo The Veteran]

My MB is the Chaintech 7NJS Ultra ZENITH (it shows in my computer details) and i don't need a review. I already know that the speciffic cpu is compatible. I just don't know if it's the same in a mobile edition also. There is no review that shows XP-M class processors as compatible or even optional because it's illogical to buy one. For starters they are rediculusly overpriced than the normal ones.
To put it simple. Is there a difference in XP and XP-M processors besides the name? Yes and what? or No?

[ZippyP.]

Is there a difference in XP and XP-M processors besides the name? Yes and what? or No?

Mobile XP processors can run at lower voltage and hence run cooler than stock XP CPU's at the same clock speeds. They are better overclockers for that reason, if you're into that, as you can bump up the voltage and hit higher speeds.

Identify your chip here: http://www.cpu-world.com/info/id/AMD-K7-identification.html

CPU comparison and overclocking info here (check out page 2): http://www.neoseeker.com/Articles/Hardware/Features/XP-M/

As a straight replacement for a desktop cpu they're fine.

[mh2360]

From what i've read about XP-Ms, technically they SHOULD work in XP motherboards, but they don't always. You would be taking a gamble here...

[budz]

I have a XP-M 2400+ AMD mobile processor in a SOCKET A 462 ASUS A7NX8 mobo. Any socket A 462 mobo should be fine with the Athlon XP-M 2600+ with the Barton Core Cpu.

[mh2360]

Any socket A 462 mobo should be fine with the Athlon XP-M 2600+ with the Barton Core Cpu.

What?

Not even remotely true, some older Socket A boards won't even take an Athlon XP! It depends completely on the model, in Jo The Veteran's case information on his board is hard to come by. Like I said before - although technically the CPU should work, there's a chance it may not, so he would be taking a gamble...

[Jo The Veteran]

From what i understand from your many posts here SOME XP-Ms work in non mobile/laptot MBs and those who do are a bit cooler than the regular ones (which is cool actually ).
It's not that i have many options left, my computer is old, REALLY OLD. I've given up trying to update it 1 year ago and now, well suffice it to say i'm willing to take that gamble.
Thaks everyone for openly speaking your mind, i'll just have to try and see i guess.

[Jo The Veteran]

OK got it, and installed it. Works good till now, no crashes or overheat or anything but it shows in almost everywhere as "Unknown CPU Type". What does this mean (besides what it actually says). Will there be any sideffects to this? Maybe not able to use MMX or 3DNow technologies. I'm thinking BIOS update may be in order, am i right?

[mh2360]

To check speed, MMX etc, run dxdiag (Start>Run>dxdiag), the processor info should be displayed there. "Unknown processor" could mean that you have the FSB or multiplier settings wrong (bus frequency should be 133MHz and clock multiplier should be 15), make sure you are getting the speed you are supposed to be getting, in your case it should be 2ghz...

If you can boot into windows and the system seems stable, then you are probably going to be OK, only time will tell though. (good luck in finding a bios update BTW )

[Jo The Veteran]

Are you sure about this?

bus frequency should be 133MHz and clock multiplier should be 15

because my MB manual sets the standards for the XP 2600+ Barton at 166 and 11.5.
BTW i found the bios, updated and all and something did happen actually. While i set the fsb and multiplier as told, i get 1.54GHz. Nice trick huh? Underclock your cpu with a bios.
And BTW, CPU is still unknown, even in the latest v9 something bios.

[mh2360]

Your motherboard probably thinks that the CPU is a regular XP 2600+ Barton, which does run at 166MHz, with a 11.5 multiplier. The XP-M however runs at 133MHz with a 15 multiplyer.

XP-M 2600+ Barton specs

http://www.cpu-world.com/CPUs/K7/AMD-Mobile%20Athlon%20XP-M%202600%2B%20-%20AXMA2600FKT4C.html

XP 2600+ Barton specs

http://www.cpu-world.com/CPUs/K7/AMD-Athlon%20XP%202600%2B%20-%20AXDA2600DKV4D.html

Multiply the bus speed by the multiplier to get the CPU speed. Using 166mhz your CPU would be slightly slower...

[Jo The Veteran]

What about the "unknown cpu" thing? Does it bother me? Is it dangerous or something? It's still unknown after the latest bios.
One last thing. If you set a cpu to run slower it will generally burn less power and exert less heat right? Will anything "Bad" happen to the cpu while running slower than intended?

[budz]

What about the "unknown cpu" thing? Does it bother me? Is it dangerous or something? It's still unknown after the latest bios.
One last thing. If you set a cpu to run slower it will generally burn less power and exert less heat right? Will anything "Bad" happen to the cpu while running slower than intended?

The cpu showing up as "unknown cpu" is fine. I wouldn't worry about it. My XP-M 2400 shows the same and I have it overclocked so the cpu spd is 2.13ghz. Why underclock the cpu if it should be 2.00ghz? When I get home from work I'll get on my other pc and post a CPU-Z screen shot of the XP-M 2400 cpu.

[Jo The Veteran]

I inputed the correct fsb and multiplier settings and now shows as an athlon xp-m alright, but the speed went down at 800Mhz!!! Help!!!

[mh2360]

I inputed the correct fsb and multiplier settings and now shows as an athlon xp-m alright, but the speed went down at 800Mhz!!! Help!!!

Does it say 800mhz in the boot screen/bios or just in Windows? After a little digging I found that Windows sometimes displays the wrong speed for XP-Ms in desktop boards, it's possible it could be running at full speed and it's just windows reporting the wrong speed.

http://www.snapfiles.com/get/wizcpuspeed.html

This little program should give you some idea.

[Jo The Veteran]

No it's in both, Bios and windows alike. I've inputed 166FSB and 11.5MP and it's back to normal (only with unknown cpu). I've also tried other MPs at the 133FSB 10.5 and 14. It always sets the cpu for 800MHz, and it kinda slows to boot up bios too.

[mh2360]

I'm betting this has something to do with PowerNow, the XP-Ms built-in mobile power saving technology. It automatically sets the multiplyer to 6 (6 * 133 = 798MHz) to save power. I think your desktop thinks it's a laptop when it recognises the XP-M as a mobile processor. The multiplier might then be dynamic, throttling up or down as you need CPU power in order to save a non-existent battery .

Now to find a way to disable it, if not you may have to live with "unknown CPU", which is better than 800MHz, or it may indeed "throttle up" automatically when you need the speed...

[Jo The Veteran]

you may have to live with "unknown CPU"

Already doing so, i'll just leave it at that.
Thanks for the info everyone.