Dual CPU PC's

[RBowyer]

Can some please give me an idea of the benefits of a Dual Pentium machine under Win98. Is it worth the cost?

[spdsk8r]

Sorry, but you can't have Dual processors in Windows 95 or 98 You have to be running Windows NT 4 or 5 (when 5 comes out) Your best bet is getting one fast processor and a lot of RAM because almost all games will NOT run on Win NT. In the future, you will be able to have dual processors with Windows 2000 which will be compatible with Win 95 and 98... If you tried with the current ver. (95 & 98) you wouldn't get any speed increase because 95 and 98 don't detect the second CPU.

[JP]

psdsk8r is right. Just to add a tidbit of information: Windows 95/98 are not "multithreaded" operating systems. This is why they do not take advantage of the second CPU.

[CMonster]

"BeOS" www.be.com has native dual cpu support, i.e. multithreaded- of course there are arn't many applications and only a miniscule amount of games that will run on it as of yet.

[Keeper1]

What about Linux? My understanding is that it is a true multi-threaded OS and can run just about any Windows software - with the right tools.

[CarverRN]

Multi-threading or multi-tasking does not mean that it can support multiple CPUs.

[CMonster]

Dual CPU support is actually common using Linux, and the Linux OS has tons of stuff to offer, games, applications, and more. But getting it configured and becoming used to it is no picnic - it's getting better but has a long way to go.

As for Linux running Window's programs - there is an experimental windows emulator called "wine" but I wouldn't expect anything truely workable to be available in the near future; "with the right tools" is right.

[tibbar]

The problem is not only the operating system has to support mult processors, be multi threaded, but to take full advantage - the application has to be multi threaded as well and there aren't too many of them on the market so far - majority of them are sophisticated 3d programs and cad programs (one for sure that works is PhotoShop5). All Corel programs ARE NOT multithreaded. Hopefully soon manufacturers of software will come up with better usage for multi processors. Have heard that games in near future will be multithreaded.

[wily]

I just came across this in a review of an Epox dual-PII motherboard on the "BX Boards" site:

http://bxboards.com/EP-KP6-BS.shtml

Under Windows NT, a special multi-processor kernal is used, as well asa special Hal.dll to integrate the two processors. Again, even under NT you cannot expect double performance. There are a number of reasons for this. Firstly most applications simply do not make provision for thread-sharing amongst processors. About the only application that springs to mind that will take advantage of this is Adobe Photoshop4. NT4 will offload certain tasks onto the second processor, so I/O tasks for example can be hived off, there byfreeing the first processor to spend more time application processing.

Another reason why you cannot expect double performance is that a great deal of hand-shaking between the processors is necessary in order to prevent bus-contention issues. Therefore the processors spend a great deal of their time simply running "After you, Claude" checking in order to prevent resource clashes, or even worse, deadlocks. The addition of a second processor will only increase speeds by anorder of 50%, while adding a 3rd would increase things only be another 25%. With 4 processors the law of diminishingreturns kicks in, with a gain of only around 12-13% when stepping up from 3 to 4 processors.

[Tony M]

Accualy, the ammount of handshaking that occurs between CPUs to support dual is not the bad. The overhead in NT is about the same as the overhead netowrking adds. If you check out the Dual Tyan Tiger 100 review you can see some benifits of a dual CPU. from my experience, a second CPU in a highly threaded environment adds about 80% performance gain and an ever greater gain for RC5
http://www.sysopt.com/reviews/tiger100/

Tony M