Windows & Dual processors

clessoulis · Post by **clessoulis** » Mon Jan 22, 2007 7:56 am

What windows support Dual Processors? Not dual core processors but actual double cpu setups. Also do the applications need to support Dual Processors or does the Os just use them as 1 combind cpu speed?

SquareHead · Post by **SquareHead** » Mon Jan 22, 2007 8:06 am

I'm going to go out on a limb and say windows xp does as well as linux. I think it is the same situation as dual core setups, you need to have applications compiled with multi core/cpu support. Someone correct me if I am inaccurate.

AntoineWG · Post by **AntoineWG** » Mon Jan 22, 2007 9:21 am

I'm not sure if XP Home supports dual processors or not, but XP Pro supports up to 2 physical processors. Single-threaded applications will run on one processor at a time but won't be able to take advantage of dual processors. Multi-threaded applications should be able to take adavantage of the dual processors just fine.

Clements · Post by **Clements** » Mon Jan 22, 2007 9:40 am

XP Home does not support two physical CPUs (as in two separate sockets on the motherboard). Nor do any of the home versions of Vista. Vista Business/Enterprise/Ultimate, XP Pro and Windows 2000 do support dual processor setups.

The home editions however all fully support CPUs with multiple cores in a single socket (such as a Core 2 Duo).

A fully enabled AMD QuadFX platform would need a pro edition of 2000/XP or Vista to work.

SquareHead · Post by **SquareHead** » Mon Jan 22, 2007 4:32 pm

Ahh so the quotation "Windows licensing is dependent on socket not cores." makes a lot more sense now.

adventure_of_link · Post by **adventure_of_link** » Mon Jan 22, 2007 10:44 pm

Windows 2000 Professional
Windows XP professional
Windows Server 2003

ps: he asked for windows OSes, not linux.

clessoulis · Post by **clessoulis** » Tue Jan 23, 2007 3:40 am

This brings me to the next question. Do any games that anyone would actually play support multi threading of 2 independant processors. I know some of the new end stuff like pcsx2 supports a dual core processor but, I doubt it has dual processors support.

Will there be any advantage realistically between having a 1ghz p3 or having dual 1ghz p3's. The only thing i've noticed that would be a nice advantage is that the server mother board supports 1.5GB of ram instead of just the 768 I have at the moment.

Last set of question. Do both processors have to be the same cpu speed? Also which processors does it choose to be the main one when runing a single application? Does it automatically use the larger one?

Deathlike2 · Post by **Deathlike2** » Tue Jan 23, 2007 4:08 am

clessoulis wrote:This brings me to the next question. Do any games that anyone would actually play support multi threading of 2 independant processors. I know some of the new end stuff like pcsx2 supports a dual core processor but, I doubt it has dual processors support.

What?

Will there be any advantage realistically between having a 1ghz p3 or having dual 1ghz p3's. The only thing i've noticed that would be a nice advantage is that the server mother board supports 1.5GB of ram instead of just the 768 I have at the moment.

Not really. Ideally it should be handled by the OS, but even then, it's not perfect. Then you have consider developers taking care to consider multiple cores.. however I personally think it is a waste of time that could be spent on fixing bugs, but what do I know...

Last set of question. Do both processors have to be the same cpu speed? Also which processors does it choose to be the main one when runing a single application? Does it automatically use the larger one?

Well, most people won't use dual CPUs (2 physical CPUs), but rather dual-core (2 processors on the same chip). I would think you ideally WANT to use the same speed... (dual core doesn't have to worry about this, since it is the same chip). This is all supposed to be handled by the OS in the end. You still won't get optimal performance, but you can certainly multitask more. IIRC, the best performance gain you can get from dual cores is like 20% in games... not 2x as you might think. I think OSes will certainly get better at handling this stuff, but you won't exactly gaining these benefits immediately. Server apps are generally ahead of this curve (they certainly factor in multi-core/processors when they write the apps.)

casualsax3 · Post by **casualsax3** » Tue Jan 23, 2007 4:18 am

The Source engine (Half Life 2) is fully optimized to take advantage of dual core setups. Get the notion of dual CPU's out of your head - they never made any penetration in the desktop world. If you're going to go dual anything, dual core is where it's at, with the AM2 Athlon X2's and Opteron 12xx series, and with the LGA775 Core2Duo.

As Deathlike2 mentioned, the biggest benefit you'll see is that your system will hardly ever slow down. Windows and Linux are efficient at scheduling processes so that the system remains responsive and usable.

Deathlike2 · Post by **Deathlike2** » Tue Jan 23, 2007 4:41 am

Well, the main difference between dual-core and dual-cpus are really simple... you want to go dual-core.

1) Dual-core have the processors side-by-side.. dual cpus require extra traces (eg, the paths between the CPUs), which increase the cost of the mobo.

2) Dual CPU means you will need another set of memory. Seriously, you would need TWICE as much memory as each CPU needs a set of memory to work with. The worst part of this is that the system is the memory is still considered separate (like, 1 GB of memory per core == system memory is 1GB each, not 2 GB "total). Dual core does not have either issue.

Edit: For a thought, you may do yourself a favor if you google about this. You will find what you need to know.