Single CPU (higher MHz) better than dual CPUs (lower MHz)?

[ColdFusion718]

What's faster (or better), a single CPU running at say 1 GHz or dual CPUs running at 700MHz each? (running same OS and applications). Just want to know what you all think because I'm thinking about building a dual CPU system and this guy downstairs says a single with higher speed is better (then again a 1 GHz costs a lot more than 2 700 MHz chips). Thank you in advance for the advice.

 

[Rich3077]

I have been wondering the same thing myself. I have 2 600E's @800
on a Tyan Tiger 100. I dont think 2 CPU's is faster untill
heavy multitasking comes into play. I did read a review that said it
would be about 40% faster than the CPU's rating.. but I am not so sure about that. One good place to get info is the forums at
www.2cpu.com
Lots of SMP geeks over there.


Rich

 

[Rich3077]

Here is an article that claims a 80% increase in speed.


http://2cpu.com/How-To/article2.htm


Rich

 

[Vegito]

I have several Dual P3 500s and they're a lot faster in calculating excel sheets in NT then my Single 733.

A LOT faster... but yes, under HEAVY multitasking.

Take RC5, dual P3 gets 2.73MK, my single gets 2.02

 

[DaddyG]

The 'Rule of Thumb' for 2 processors, is 1.6 - 1.8 times the speed of a single processor. Naturally, you OS AND Application have to be capable of utilizing 2 processors concurrently.

 

[Rich3077]

DaddyG,

About the programs having to support SMP. None of my programs do.. exept for Win2000. When I mutitask Win2000 evens the load between CPU's very nicely.. and can be seen in the task manager.

As an experiment I opened ACDSEE to a folder with over 2,000 images
and watched the task manger as they loaded. Even though ACDSEE is not an SMP program both CPU's worked at 100% untill the images loaded.

However with a light load on the CPU's.. for example just basic web surfing.. I dont think much perfomance is gained. Its really hard for me to tell because at 800MHz or higher I cant see any performance gains anyway because of other system bottlenecks. As soon as I have the extra cash I think my next upgrade will be 10,000 RPM SCSI hard drives.

One nice thing about dual CPU's.. when a program crashes and eats 100% of the CPU you still have a CPU left to kill the process... so you get much less crashes and freezups. Its also nice to be able to do HEAVY multitasking... like burning a CD while you play Q3A.

I am not trying to sell anyone on SMP systems.. just sharing my experiance. Most people who have a SMP setup wont go back to the old single CPU. I am an SMP newbie myself.. but I am hooked.


Rich

 

[Caliboy]

The answer really depends on what the computer is being used for and the applications you are running. If you're doing everyday Windows stuff then the 1Ghz CPU will be faster. But if you're doing a lot of work with 3D rendering and other CPU intensive stuff like Quake3 than the dual 700mhz would offer better performance.

 

[DarkManX]

I have also been wondering the past few days if I should build a Dual CPU box. not gonna use P3's probly celly 500's. I was thinking of useing it as an mp3/file server with an IDE raid setup. and maybe HTTP/FTP server. Would deal CPU's benefit this setup?

 

[DaddyG]

Rich3077,
You're absolutely correct in what you say. Some applications, which are SMP aware, can 'sporn' multiple threads, which can be processed in parallel. Some applications create situations where, each processor locks out the other, due to resource conflicts, and the OS spends more time resolving conflicts than the application spends doing useful work. The term 'Deadly Embrace' comes to mind. I have a very simplistic situation, consider that you are recalcing all the cells in a very large spreadsheet, if the spreadsheet program could spawn 2 processes, and have each processor calculate half of the cells, you get my drift.

 

[DaddyG]

Rich3077,
I don't know anything about the application that you mentioned, but it is possible that what you are seeing, is WIN2k multi-tasking when providing services, say through an API, for the application. If an application uses a single thread, its pretty near impossible to run it on two processors concurrently.

 

[Hyper99]

How about a Triple cpu design with
different kind of cpu
You can use K6-2 500, Celeron 300A O/C to 450, and PIII 500 O/C to 600
They perform like 1.55 gigahertz in multi tasking ability
But I think is too complicated and wouldn't serve our needs.

 

[ColdFusion718]

Thanks a lot for all your opinions. I will wait for a good motherboard or until Tyan gets its act together with the Tiger 133 board. The reason I want to build a dual system is not to be some badass on campus, many of my friends will be living off campus next year and I thought I'd hook them up with a dedicated server for them to play CounterStrike or store files, etc. Also since I'll be an RA, I can redesign the dorm's website into a more robust one and having a dedicated server helps elminate all those system problems with the school's slow servers. Thanks again for the input. If anyone has anything new to tell me, email me at pqtat@ucdavis