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Can any CPU be used in a multiprocessor system??

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Anonymous
a b à CPUs
March 5, 2002 8:27:14 PM

Before I begin, keep in mind that I'm not a computer guru. So don't rip into me for trying to learn more. (Some people who respond to questions in this forum are viscous.)

First of all, am I correct in saying that only programs that are built to use multiprocessors can benefit from a multiprocessor system? If a program can only use one CPU at a time, then if I was running 5 or 6 programs simultaneously, would each program use either CPU or would they all use the same one?

Secondly, can any CPU be used in a multiprocessor system? Is there a big difference between... let's say, the Athlon XP and the Athlon MP? Or could 2 Pentium 4s be used in a multiprocessor system?
Would there be any benefit to using a multiprocessor system as your desktop vs. a single processor system... if in both cases the CPUs were the same speed?
March 5, 2002 8:34:06 PM

Quote:
First of all, am I correct in saying that only programs that are built to use multiprocessors can benefit from a multiprocessor system? If a program can only use one CPU at a time, then if I was running 5 or 6 programs simultaneously, would each program use either CPU or would they all use the same one?


Only stuff designed for MP can use both at the same time, i'm pretty sure by having two cpu's with non MP programs they will just use 1 cpu each so two different programs could be using different processors.

Quote:
Secondly, can any CPU be used in a multiprocessor system? Is there a big difference between... let's say, the Athlon XP and the Athlon MP? Or could 2 Pentium 4s be used in a multiprocessor system?
Would there be any benefit to using a multiprocessor system as your desktop vs. a single processor system... if in both cases the CPUs were the same speed?


No not all of them can i believe. The Athlon MP's are guaranteed to work in a SMP environment while the XP's are not even though you could use them that way but there's no warranty. Not sure about the p4's.

Some say it's more fluid, no jerkiness or slow downs when running a SMP system so there is an advantage of a single system if you can afford it.



<font color=red>:</font color=red> <font color=white>:</font color=white> <font color=blue>:</font color=blue>
March 5, 2002 8:35:03 PM

Yes, only programs explicitly SMP-enabled will benefit from multiple processors. However, as you say, in W2k or XP Pro, different programs can be run on different processors.

Athlon XPs can be used in dual boards, but you don't have official support from AMD in case something goes wrong (not that you'd really need it, but that's another conversation).
Athlon MPs are unlocked and certified to run in dual systems, that's the only difference.

Two P4s cannot (AFAIK) be run in a dual system, you'll need Xeons for that.

The benefits are that either you can run more than one program fluidly, or take advantage of SMP-enabled programs.

<font color=orange>Quarter</font color=orange> <font color=blue>Pounder</font color=blue> <font color=orange>Inside</font color=orange>
Don't step in the sarcasm!<P ID="edit"><FONT SIZE=-1><EM>Edited by FatBurger on 03/06/02 10:06 AM.</EM></FONT></P>
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March 5, 2002 8:38:17 PM

Quote:
am I correct in saying that only programs that are built to use multiprocessors can benefit from a multiprocessor system?

Pretty much.


Quote:
If a program can only use one CPU at a time, then if I was running 5 or 6 programs simultaneously, would each program use either CPU or would they all use the same one?

The operating system would decide which program was sent to which processor. It would attempt to evenly split up the load between the two processors.


Quote:
can any CPU be used in a multiprocessor system?

While some processors may work in a multiprocessor system without proper validation, it is generally not advised. You should stick with those that have been specifically designed and optimized for a multiprocessor system.


Quote:
Would there be any benefit to using a multiprocessor system as your desktop vs. a single processor system... if in both cases the CPUs were the same speed?

Yes, your operating system could use one processor for its own housekeeping, allowing you to dedicate an entire processor to whatever application or game you are running. If you frequently multitask, your applications could be split between your multiple processors. You would likely see the response delay when you click to perform an activity drop considerably.

Only you can say if it is really worth it to purchase such a system. If you are heavy into simultaneously running many applications, or running processor-intensive applications designed to be multithreaded, you may want to think about it.

-Raystonn


= The views stated herein are my personal views, and not necessarily the views of my employer. =
March 6, 2002 3:22:04 AM

Quote:
Athlon MPs are unlocked and certified to fun in dual systems, that's the only difference



And what fun they have!

"The Cash Left In My Pocket,The BEST Benchmark"
No Overclock+stock hsf=GOOD!
March 6, 2002 4:13:06 AM

.

I run duals because i multitask between notepad, outlook express and winamp :lol: 
March 6, 2002 6:51:42 AM

Hey Divine,
another thing to watch out for is the a dual cpu motherboard. I understand ( so dont flame me if im wrong) that some dual mobos dont have a dedicated bus for each CPU. Whereas the high-end dual mobos do have a dedicated bus for each CPU. Ergo, the low-end boards wont have near the performance as high end ones.
PS: you pay out the nose for those dedicated busses too.

Benchmarks are like sex, everybody loves doing it, everybody thinks they are good at it.
Anonymous
a b à CPUs
March 6, 2002 7:41:26 AM

What does it mean to have dedicated bus for each CPU? And how pricey are we talking?

Also, do multi-CPU motherboards typically have all the same things as a single chip mobo? (Like a 4x AGP and the likes that you would find in really sweet gaming system?)

I typically have at LEAST 5 programs running at the same time. (Music, web, video editing and a game, etc.) I really want something that can easily handle me doing a bunch of stuff at once AND kick-ass doing it. :)  I'll probably be ready to build this once the Barton MP is out.

Off the subject a little.... are there any new graphic cards coming out soon... Like 8x or something like that?

By the way... thanks everyone for the help!
March 6, 2002 11:37:14 AM

OK,

Dedicated busses:

The bus = little copper lines coming from the CPU to the memory and northbridge

If a motherboard has two CPUs but only one bus. That means both CPUs have to share that bus. Which means if you run some hardcore programs, the system bus cant keep up and wont move data from both CPUs very well.
Try this analogy. You have two very smart people ( your two CPUs) asked to do a lot of hard tasks at once. Obviously you want their answer back quickly. But then you tell them they have to write the answer with their toes (a single bus motherboard). Which would be a very slow process.
So, you'd have a lot of computing power, just no way to get that info back to the screen quickly... cuz your motherboard bus clogged with info.
If you have dedicated busses, that means each CPU gets it own "little copper lines" so all the info it generates can flow freely, and not have to share a bus with the other CPU.
Cheap dual mobo 120-200$ range.
High-end dauls 400+ dollars (and go WAY up from there)

Second, Im not sure its even possible to run a video editor, game, music, web etc all at once. Even with dual moniters. If your going to video edit, then duals would probably help. Editing punishes a system.
For all the rest, a high end single CPU solution is the better choice.
Do dualies have all the "stuff" on them too? Many of them do yes. But just look at each one, and select the one with features you like.
Graphics cards? Hell yes... the geforce 4. Read all about it here at Toms and anandtech.com, firing squad, arstechnia and just about any hardware sight. Its really nice ( awaits the flame from ATI fans) Not sure if its agp 8x compliant. Have to look into that.

PS: on a side note, running multiple apps at once is memory intensive. You would benefit from a system with high memory bandwidth like the P4 and its latest mobo (with RDRAM). By december of this year, new motherboards with new bus speeds will be out. THey promise to be very fast, and would likely solve the "clogging" issues i discussed earlier. These are for the AMD Hammer.
For the Pros and Cons of Intel and Hammer chips. See the other 8 million posts on this board about them :) 

Benchmarks are like sex, everybody loves doing it, everybody thinks they are good at it.
March 6, 2002 4:05:39 PM

lol
I'll fix it.

<font color=orange>Quarter</font color=orange> <font color=blue>Pounder</font color=blue> <font color=orange>Inside</font color=orange>
Don't step in the sarcasm!
March 6, 2002 5:30:01 PM

One other thing to keep in mind which was hinted at here but not explicitely said yet is that if you have a dual CPU system, what OS you have is <i>very</i> important. Last I knew, if Win9x is unable to even use two CPUs. If you load Win9x on a dualie system, it will still only be using one processor. Hence if you plan on going the dualie with Windows route, you need Windows NT or 2000. Linux on the other hand, is always friendlier about these things.

On a related note, does anyone know if (or what versions of) WinXP actually supports SMT? I've been avoiding WinXP like the plague, but it would be interesting to know if MS finally incorporated multiple CPU support into one of their 'home use' OSs. I just tried finding out by looking at Microsoft.com, but that's about as easy as finding a needle in a haystack on the surface of Pluto.

<pre><font color=green>//error-proof coding</font color=green>
<font color=blue>void</font color=blue> main(){<font color=blue>return</font color=blue>;}</pre><p>
March 7, 2002 1:51:01 AM

Windows xp pro supports dual cpus, home does not.

"The Cash Left In My Pocket,The BEST Benchmark"
No Overclock+stock hsf=GOOD!
March 7, 2002 2:08:39 AM

that is one of the difference's between the EV6 bus and Intel's bus.....

Intel's dual boards always share the same bus no matter what, EV6 *Thanks to the wonderful Alpha gods* was design to give each cpu its own bus, I believe up to 16 cpus at once. Anything higher is clusting, if I am wrong let me know........

MeldarthX
March 7, 2002 2:20:58 AM

I have a book which states:

Windows 2000 Server - Two way SMP.

Windows 2000 Advanced Server - Four way SMP.

Windows 2000 Datacenter Server - Sixteen way SMP.

Doesn't actually mention W2K Pro. Clarification on it please.

<b><font color=red> :mad:  DELETE THE "EVERYTHING'S GONE QUIET" THREAD!!! :mad:  </font color=red></b>
March 7, 2002 3:20:00 AM

W2k Pro supports two processors.

<font color=orange>Quarter</font color=orange> <font color=blue>Pounder</font color=blue> <font color=orange>Inside</font color=orange>
Don't step in the sarcasm!
March 7, 2002 11:54:25 AM

well i for one would think it would be nice if amd pulled their finger out of their ass, and started letting other companies bring out solutions for dual setups. for some reason a dual setup on an nvidia chipset would seem pretty sexy. or a dual sis chipset, talk about stable. but for now, we are stuck with a couple pci slots that the majority of people won't use and non-functioning usb.

I run duals because i multitask between notepad, outlook express and winamp :lol: 
Anonymous
a b à CPUs
March 7, 2002 6:15:49 PM

Is the bus speed the same thing as FSB?

Also, if the P4s' FSB is something like 533 and AXP is only 266... shouldn't that make the P4 kick ass over the AXP? ... but it obviously doesn't.

This will probably sound like a stupid-ass question, but why don't they make the memory and bus speed the same speed as the CPUs?
March 7, 2002 8:14:44 PM

FSB = Front Side Bus

Yes that's the bus speed of the motherboard, CPU (with multiplyer gives CPU speed), chipset and RAM.

P4's are 100MHz bus speed quad pumped = 400MHz usually.
The Athlons are 133MHz double pumped for 266MHz.

Because the base speeds are 100 and 133 respectively, the AMD processors are able to outperform the P4.

Not sure about the 533MHz ones. It would suggest 133 x 4. The reason AMD chips are better performers clock for clock is the architecture involved. Intel are chasing the MHz, because most consumers want big MHz. They can't and/or won't understand how a slower processor can be a better performer.

<b><font color=red> :mad:  DELETE THE "EVERYTHING'S GONE QUIET" THREAD!!! :mad:  </font color=red></b>
March 7, 2002 8:30:59 PM

Also keep in mind that RAM plays a huge part in multitasking, even with dual CPUs, so if you do go dualie make sure to get lots of RAM!!!

Jesus saves, but Mario scores!!!
March 8, 2002 11:58:32 AM

Thanks. It would figure that a product which theoretically should have the same kernel actually doesn't. (Or else that MS put in a limit to their software.) Hmm ... didn't MS just recently state in a court case how they couldn't offer various solutions because it would confuse the customer when they tried to hedge around why they couldn't just release a version of Windows without IE integrated? It would be funny if it weren't so sad. (Or maybe it would be sad if it weren't so funny?)

<pre><font color=green>//error-proof coding</font color=green>
<font color=blue>void</font color=blue> main(){<font color=blue>return</font color=blue>;}</pre><p>
March 9, 2002 7:22:08 AM

Bah Winblows and smp aren't the best combo.....:)  That's why monster super computers run a unix.....or a form of it....Look at some of Sun's monsters 168 cpus without clusting.......ok, I just corrected myself.......:) 

small SMP windows isn't bad, but I believe the code itself just can't handle something that high.....or powerful


MeldarthX
March 9, 2002 7:29:08 AM

Sorry, but when you get into server market, stablity is king over everything else. That is why its taken AMD so long to release the new MP chipset. They wanted to make sure all the bugs were out of it.

Sorry SiS does not have a good rep for being stable in the business world. Nvidia is still the new kid on the block and would not be taken seriously in the server chipset business. AMD is clawing every inche. Hell even Intel isn't taken serious in large server business, that is owned by Sun, IBM, and Compaq and HP are kinda there.

The new A7M-D board from Asus has the new smp chipset from AMD......good chipset, very good platform. Biggest problem, mb manufactures that don't follow the ref board layouts.

AMD will slowly break into the workstation and lower end server market, but only after they have proven themselve. They are slowly doing that now.

MeldarthX
!