Dual Core Processors

[welsh blackbird]

I know that XP Home only supports single processors, but does it support dual-core processors? Or do I need XP Pro?

Thanks

[jimmyjimjim]

A quick search of Microsoft.com seems to imply that dual core processor are treated as a single processor from a licensing point of view, and there's a comment in one of the ms forums about home displaying two processors in task manager correctly, so I'd assume so. Service pack it to the hilt first, though!

[225]

pretty sure it will do. Professional does.

[munter]

As I understand it XP will treat a dualcore processor as one processor. Win2000 isn't so smart and will treat each "core" as a seperate processor. (Which in fact they are, just printed next to each other).

[_deejay_]

Surely Home will run the single processor kernel (i.e. will not be capable of scheduling jobs across 2 CPU cores, whether they're one one physical slot or not).

I'm not sure though - XP home - yuk!!

D

Edited to add: scratch that, seems it's proven to work, see here:http://hardware.mcse.ms/archive23-200



>> Edited by _deejay_ on Wednesday 5th April 13:09

[munter]

_deejay_ said:

Surely Home will run the single processor kernel (i.e. will not be capable of scheduling jobs across 2 CPU cores, whether they're one one physical slot or not). I'm not sure though - XP home - yuk!! D Edited to add: scratch that, seems it's proven to work, see here:http://hardware.mcse.ms/archive23-200 >> Edited by _deejay_ on Wednesday 5th April 13:09

It would have but fortunately Microsoft realised that this "new" technology needed different rules while they were building XP. It's win2000 that gets interesting! If you have a twin dual core system you essentially have 4 processors. If the BIOS isn't written well then the 1st 2 processors are on the same chip. As win2000pro can only use 2 procs it'll use the 1st two which are on the same chip! If the BIOS is written correctly then it will use one proc on each chip to get the max performance it can.

With XP and after they avoid all this by treating one physical device as 1 processor for the licence.

[Zad]

But surely after the PC has booted into the OS it doesn't use the BIOS again, it talks to the I/O and configures the system via it's own device drivers. I don't think it's a licensing issue as such, just that dual core with HT wasn't dreamed of when Win2K was being written.

[munter]

Zad said:

But surely after the PC has booted into the OS it doesn't use the BIOS again, it talks to the I/O and configures the system via it's own device drivers. I don't think it's a licensing issue as such, just that dual core with HT wasn't dreamed of when Win2K was being written.

When the OS loads it gets info from the BIOS about whats out there. The BIOS says heres x number of processors 0,1,2...etc. And windows will pick them up in order. So if win2000 only has a licence for 2 procs it'll run on 0 and 1. And ignore any others.

Your right about it not being imagined when win2000 was designed. But they could have carried on the same licencing into XP. Fortunately they didn't. Not that the staff employed by Microsoft UK could understand dual core processors when I first raised it with them. It was like trying to explain the internal combustion engine to a 2 year old.