twin cpu motherboards..any good??

[greatant]

Originally posted by Gnuthad
Last time I checked, the bandwidth between a CPU and the memory was far lower than the bandwidth internal to that same CPU. Face facts, having twice as many CPUs competing for the same limited bandwidth for memory will NOT make things any faster than with a single CPU.

Bandwidth between the cpu and memory is larger than the internal bandwidth of the cpu, the speed however is a different matter. The internal cpu would be a LOT faster than between cpu and memory.

Thousands of people have shown that their systems are limited significantly by (lack of) memory bandwidth. Don't believe me? Go buy a SDR/DDR mainboard, put in 256M PC133 with even a lowly Duron 600. Run through your choice of benchmarks. Now, without changing anything except for the memory, swap out the SDR for 256M PC2400 DDR and run those same benchmarks again.
I'll bet you $100US that your system leaps ahead with the increase in memory bandwidth provided by the DDR over the SDR. Unless you have some way of doubling that same bandwidth with you insert a second CPU in your motherboard, you ARE throttling back your system by using 2 processors.

I'll bet you that most SDR/DDR mobos see no difference in speed whether using SDR or DDR.

The only way you would see a significant (read: noticable) speed increase with two processors over a single processor is when your application is written in such a way that each processor reads/writes main memory while the other is actively processing. For the record, Windows is not written to handle such events so, while you might see a slight increase in speed with a single application, the only way you will truly see an increase is by running enough applications that a single processor is taxed.

There is a whole range of Win2k Operating Systems that support more than 1 Processor.
Win2k Professional - 2 Processors
Win2k Server - 4 Processors
Win2k Advanced Server - 8 Processors
Win2k Datacenter Server - 32 Processors

I don't know about your application, but unless you are actually running multiple threads simultaneously you will see next to no benefit from a dual processor system.

Agreed

[Gnuthad]

Yes, I have around 20 threads open but all except for Explorer are pretty constantly sitting at 0% CPU usage. Explorer flicks up to 5% or 6% occassionally. How much benefit am I getting at that time from Dual CPU? Absolutely none. The only benefit I ever get is when I am actively running more than 1 thread, actively being when the thread is actually consuming CPU power and time.

[64026402]

Originally posted by martinus


That doesn't hide the fact that you were making ifalse statements. For starters you claimed that my previous comment is "incorrect". Please specify which sentence is "incorrect".

While you are at it, please provide proof of a scenario where 300 threads are in status ready or running. I am typing this reply on a one-cpu system which runs an industrial strength RDBMS plus an SAP R/3 central instance, and the number of threads and processes competing for the cpu resource can go up to 1, 2, or 3. This system would most definitely benefit from a dual cpu, but I tell you what, it would benefit ten times more from more RAM, and to a lesser extent from more and faster disks to spread out I/O. Because seek times are in the area of milliseconds, and any single/dual argument just goes away.

Having said all that, I am not arguing your point that a dual cpu system responds better to short term load like a keyboard IRQ or a window to be drawn. Because this is exactly one of those scenarios where more than one thread (or IRQ) is competing for the cpu. Whether the microsecond delay you face on a mostly idle single cpu system is noticable is up to you. Actually this could well be a platform issue (AMD/VIA vs. P3/BX).

QUOTE
depends on your application. Dual increases throughput, not speed. So if your load average (no. of processes in state ready or running) is going above 1 you'll benefit from additional cpus.QUOTE

I was simply pointing out that anyone using a dual when opening any program will notice a difference. How much and how long the difference lasts depends on how the program is written.

At this moment I am running 2 folding clients and an answering machine on my main 24 hour machine. I show 25 pocesses, 299 threads, and 3 programs running. If you run the same you can check your own performance monitor. I would imagine that would be proof enough.

[64026402]

Originally posted by Gnuthad
Thousands of people have shown that their systems are limited significantly by (lack of) memory bandwidth. Don't believe me? Go buy a SDR/DDR mainboard, put in 256M PC133 with even a lowly Duron 600. Run through your choice of benchmarks. Now, without changing anything except for the memory, swap out the SDR for 256M PC2400 DDR and run those same benchmarks again.

I'll bet you $100US that your system leaps ahead with the increase in memory bandwidth provided by the DDR over the SDR. Unless you have some way of doubling that same bandwidth with you insert a second CPU in your motherboard, you ARE throttling back your system by using 2 processors.

No one can argue that faster memory won't help speed, but memory speed increases do not give the same computer speed increase.

Going from sdr to ddr can double memory bandwidth but gaines in program speed are usualy in the 5-10% neihborhood. P4s with subtantially faster rambus are still not as fast as a similar clocked athlon.
Going dual procs gives you the ability to double the programs you run effectively or run an SMP program nearly twice as fast. It is a much more noticable difference than a memory change.

[64026402]

Originally posted by Gnuthad
Yes, I have around 20 threads open but all except for Explorer are pretty constantly sitting at 0% CPU usage. Explorer flicks up to 5% or 6% occassionally. How much benefit am I getting at that time from Dual CPU? Absolutely none. The only benefit I ever get is when I am actively running more than 1 thread, actively being when the thread is actually consuming CPU power and time.

You got me there. If you stare at the computer screen and don't have any meaningfull programs running you will not benifit from dual cpus.

On the otherhand you could be folding while your doing nothing.

[leperMessiah]

Originally posted by Upaboveit
Go and open task manager. How many threads are running?

Quod erat demonstrandum.

Finally a voice of reason.

Why do all these ppl who have no experience jump in and basically talk crap?

A duallie may not be as fast in benchmarks but they definitely feel faster and more responsive.

My advice is to only listen to those who actually have and use Dual systems.

Also Dual is far more stable.

[saba]

Originally posted by Gnuthad
Yes, I have around 20 threads open...

You are looking at processes. I have 'only' 340 threads chugging away right now. How many do you have?

[MichaelMR2]

I think the answer to your origional question without DIGRESSING, is no, you will not notice a DRAMATIC increase in performance

[martinus]

Originally posted by 64026402


At this moment I am running 2 folding clients and an answering machine on my main 24 hour machine. I show 25 pocesses, 299 threads, and 3 programs running. If you run the same you can check your own performance monitor. I would imagine that would be proof enough.

right, but these 299 threads are not technically "running". I bet 297 of them are "sleeping" or "waiting", only the two folding clients are competing for the cpu resource (albeit on the priority level of the system idle process). That, of course, is the whole point of a multitasking operating system.

[64026402]

Originally posted by martinus


right, but these 299 threads are not technically "running". I bet 297 of them are "sleeping" or "waiting", only the two folding clients are competing for the cpu resource (albeit on the priority level of the system idle process). That, of course, is the whole point of a multitasking operating system.

Threads don't sleep, they are actively pushing for the next peice of proc time and 2 procs can do twice as much in the same time.
Thats the power and the speed.

[Webmaster_Zeus]

Originally posted by 64026402


Threads don't sleep, they are actively pushing for the next peice of proc time and 2 procs can do twice as much in the same time.
Thats the power and the speed.

Your right, they don't sleep, these threads are using the processors in miliseconds intervals, which is so fast that the computer registers it as zero percent usage.

Anyways back on topic, no no significant speed increase unless you run a lot of applications at once, I myself tend to find dual processors more stable as I program a lot and write programs which tries to access memory blocks which aren't allowed and it tends to chew up the whole 100% of one cpu which saves a lot of hassel of restarting but allowing to close to program immidiately.

I'm planning to add scsi hard disks to this computer which in turn will make things a lot faster as other factors do contribute to performance.

If you want to see a speed increase, add a scsi 160/320 controller card along with the corresponding 68/80pin scsi hard disk and u'll notice a huge increase in speed, as it did for my friend with his existing Xp1600 with 768mb of DDR333 ram.

[64026402]

Originally posted by Webmaster_Zeus


Your right, they don't sleep, these threads are using the processors in miliseconds intervals, which is so fast that the computer registers it as zero percent usage.

Anyways back on topic, no no significant speed increase unless you run a lot of applications at once

If your not running a lot of apps then you just have an expensive door stop. Everyone I know pushes their computer pretty hard.
Even newbies generally open files and download and unzip at the same time. Duals are just evolution. Nothing fancy.
Just a V8 engine instead of a 4 cylinder. Processors are reaching a point where Ghz increases don't really help that much.

I had been board with single procs for a while. Faster processors didn't impress me. I was waiting for a substantial change in processing to save the day. Thats when I tried a dual setup just for grins because it was cheap. I was shocked at the affect. It did so much so fast I couldn't understand why there wasn't more of a fuss. So DUALS ARE GREAT, YOU SHOULD GET ONE.
I wish some one had told that to me some time ago.

[martinus]

Originally posted by 64026402


Threads don't sleep,

you have just disqualified yourself from being taken seriously. I suggest some reading on operating system concepts.

[64026402]

Originally posted by martinus


you have just disqualified yourself from being taken seriously. I suggest some reading on operating system concepts.

Explain a "sleeping thread", then you might read a little yourself.