AMD 64 X2 4000+ slower than AMD 64 3400+ - why?

Do you see one or two graphs for CPU Usage in Task Manager?

One.

Yes, it should say Multiprocessor ACPI.
That is why you only see on.

I would look at the drivers again.
Make sure you take the option to "Specify" and not have it search.

It's slower because the 3400+ is actually faster, but only has one CPU. As you noticed, the HAL you have does not allow the 2nd processor to operate.

i have seen this before (its very rare it ever happens but norm windows not picking up that it has 2 cpus running)

update your bios

if your useing XP home i think its alot harder to change the ACPI to muti cpu mode with out doing an windows repair install

pop the XP disk in and restart the pc and make sure its set to boot from CD
after you have Pressed {any key to start setup} pressing i think F5 (i may be not right) at the start of the Blue screen when its doing the setup it then give you the options on what HAL you can use look for mutiprocessor ACPI then press enter
press enter when it gets there press F8 then it Should Find your windows Press R and it should do an Windows repair install (If it does not DO not format your hdd heh unless you want to) once its done there should be 2 cpus

ssalim norm install of XP you norm do not need to do all of this (you may be useing an Old windows disk that does not have SP2 on the disk)

(long time from when i done it i Edit this post in an min as i have to restart my pc to test it)

Isn't there a dual core optimizer thing you can download from AMD?

Just looked in google. Here is a guide for it.

http://www.xtremesystems.org/forums/showthread.php?t=81...

If you only see one core in task manager then you probably need to update your bios.

The dual core optimizer needs to be installed after your PC is properly recognizing and using the dual core processor. It only fixes timing issues with some programs and games using the X2 CPU, it has nothing to do with whether or not your PC is detecting and using both cores.

Ok I reinstalled Windows and it seems to be ok now. I can see two cores in CPU-Z and task manager. So 3400 is faster than x2 4000+... I see, that sucks. I was hoping it would be faster, in a way.

Overclocking this x2 4000+... is it recommended? I heard reviews on NewEgg that they can overclock this easily.

Yeah, it's pretty easy. You should read up on it first, though - if you don't you will probably hit a limit without knowing what it is. Here's a good guide:

http://www.neoseeker.com/Articles/Hardware/Guides/a64oc...

The 3400 may benchmark faster, but in the real world, the 2 cores will realize better performance. You don't have to worry about specially configuring Windows to the very minimal amount of tasks or background resources running to get the best performance when gaming for example. The X2 will have one core to handle background tasks while the other for running the game or app. You will especially see a big improvement when running a game or app that is multi-threaded and can make use of both cores at once.

X2 4000+ 2000 MHz x 2 cpus
64 3400+ 2200 MHz x 1 cpu
if i remember right for 939 and am2....back on 754 you could have a 200mhz speed boost with half the cache and the same rating....

So in single threaded apps the 3400 will be faster but for anything that uses dual the X2 will pwns the 3400 over...  

And even if apps are not multi-threaded, the 2nd core will help ensure that any one process does not slow down the hole machine.

The X2 4000+ is definitely better so long as you have both cores working. Don't worry :>

Ok thanks all...
re: Ethel... I read that document but I can't find anything like that in my BIOS... it's American Megatrends v02.58...

CPU Configuration:
Speed: 2100MHz
Current FSB Multiplier: 10.5x
Max: 10.5x
Able to change freq: Yes

So it's already maxed?

Under JumperFree Configuration:
AI Overclock timer: [standard]
I could choose between standard, Overclock 5% 10% or 20%

You have to increment the FSB speed, but you must read the guide as before that you have to:

1) Lower the Hyptertransport Bus multiplier to 4x
2) Set a memory divider to make sure you're not inadvertently overclocking the RAM.