According to this page...

http://www.microsoft.com/windowsxp [...] sing2.mspx

XP Home has no "Scalable processor support – up to two-way multi-processor support." which leads me to believe that my Athlon 64 X2 3800+ is going to waste by running only one core. Also it does seem like my new system isn't that much faster than my previous (which had a 3.4 GHz P4 w/ HT). Is it true that Home limits your performance?

Do you have two CPU graphs showing in task manager?

Yes.

Then I wouldn't worry too much, If you are really concerned try and get your hands on a copy of XP Pro which with release of Vista someone may give you their old copy.

Dual core cpu's are not the same as multiple processors. XP Home handles dual cores just fine. If you have two graphs in task manager windows sees and can use both cores.

If you had multiple processors your motherboard would have 2 or more Athlon 64 X2 3800+'s.

Ah, I see. Thanks then.

Its not that simple

Windows XP HOME NO but will not hurt CPU at all
Windows XP PRO Yes and no , if software is written for it but can handle multy CPU if software is qritten for it
Windows Vista Yes on both / addess and uses both cores and also Quads as well . Just need more software to come out to take advantage of this and then the results will be so much sweeter.

XP Home will support even a Q6600, i.e. all 4 cores will be used.
I found this on various pages on Microsoft's support site. There used to be some bad news in this area but they fixed XP Home and it's fine now.

You don't really need XP Pro, most likely, unless you're on a network or using the PC as a Web Server.

I got myself XP Media Center, it's a cheaper version of Pro with support for watching/recording TV. I see 4 graphs in Task Manager when I run DVD Shrink or Xing Encoder.

I have XP home OEM. It sees all four cores in task manager and you can see them being used. Set Task manager to be on top all the time and monitor the CPU usage. You will see that all cores get stressed. As far as the program using all of the cores, and using them efficiently, that is up to the program.

I did this last year when I upgraded from single core to dual.
Here is the link http://support.microsoft.com/kb/896256 Microsoft update(KB896256)
AMD has a fix for this too.I tried to give you a link but for some reason it comes out bad.
Just search for AMD optimizer and you'll find it
I did both of them and I had no problem ever since.

i dont think that the XP operating system (as a program) can utilize 2 core but is more than capable or running programs on them, im doing that now

I already patched XP with that Dual-Core hotfix and also downloaded AMD's Dual-Core drivers and Dual-Core optimizer. Everything seems to be running a lot better now, though I haven't tried any games yet. Also, when I benchmark the CPU in Sandra Lite against a AMD Athlon X2 3800+ (which is what I have), somehow my processor comes out being better than the reference. Weird, huh?

Huh. I wouldn't complain if it comes out faster

It might be that you have faster memory or something than their reference system.

My CPU comes out 2% better than reference in Sandra too Maybe it's because it's a G0 stepping and their reference was a B3, I don't know. Either way, I'm not complaining

Agree with aevm (as usual). You definitely know your stuff.

If I recall, Microsoft licenses XP Home and Pro by sockets. Home can only use one socket, and Pro can use up to two. Since all the cores on a q6600 are on a single socket, XP Home is still good to go with that CPU.

I also have four cores in task manager with XP Home, and Flight Simulator X SP-1 uses all of them, to different degrees. Core 0 is almost always pegged, and the other three average about 40-50% usage.

-G

XP home will support mutli core CPUs. What it won't support is multi socket machines. For example, XP home does not support multi socket (two processor, four core) configuration of AMD's Quad FX.

But since Quad FX sucks butt and AMD gave the shaft to all of those customers by promising 8 core (dual quads) upgrades this summer I wouldn't get it!

That a technical term?

Yes. So is megatasking and platformance.

Wonder if the copy writer who coined those phrases got a bonus, or just a pat on their salaried back