Multi-tasking?

Mainframe computers don't have a problem with multi-tasking, but personal computers always work slower when they have to do more than one job at the same time.
At least that is my experience in spite of all the years of talking about multi-tasking.
For instance, when my AVG scanner suddenly starts running everything starts working slow.

This is what AMD says :

Does the "AMD Athlon 64 X2 Dual-Core Processor" really makes a difference for multi-tasking and which one do I have to buy to make a real difference, because they aren't cheap either ?
Is there really an improvement in multi-tasking during all these years ?
I never noticed it.

 

Hi,
You won't feel the difference if you run everyday programs. Or even games. Besides, your mb and software have to be capable of taking full advantage of the offered.
What is the heaviest application you wanna run? If it's only a game, and no 3D animation monster, you can easily go with the single processor.
Mrk

 

Dual CPU is always a good idea against obsolescence, consider this, currently I am using a ancient dual P-III 850 to write here, the PC still runs all the modern relevant apps with ease, even after 7 years, I have recently upgraded my other dual XP Athlon 2800 to the current dual XP 64 PC, I intend to run this machine with minor upgrades for at least 5 more years, so in long term, its a good investment.

For multi tasking, nothing beats a dualie and I mean nothing, I can be run the defrag while compile a program or do some video audio rendering and surf at the same time provided my memory doesn't run out.

 

Well, part of your answer lies in your question... you seemingly notice poor multitasking most when you use a peripheral device, namely your scanner. Most modern apps themselves can multitask fairly well on either a single core, single CPU PC or a Symmetric Multi-Processing (SMP) PC. The bottleneck often isn't sharing the CPU anymore, but rather often lies somewhere else. Mainframes don't often have a wide variety of peripherals hanging off of them and they have large amounts of dedicated memory as well as high-speed drive arrays; thus, multitasking seems far more efficient. Your scanner slowdown might be related to a poor, inefficient driver hogging the CPU; an inefficient driver causing a hardware bus / memory contention issue; an insufficient amount of RAM causing frequent virtual paging, swapping, and thrashing; and/or a slow harddrive which is being pushed to its limits with the storage of the scanned image as well as normal OS activity and possible virtual memory paging.

Honestly, I doubt the real culprit in your case is the CPU. It could be, but rather I think it may be RAM or harddrive related. There is certainly nothing wrong with going out and upgrading to a dual-processor or dual-core processor PC; however, before you go out and spend extra money, I would definitely investigate whether you have sufficient RAM and whether you have a good high-speed harddrive or even harddrive array. You might be amazed how much more effective at multitasking your system becomes if you save money on a new CPU and instead ensure that you have, say, 1 GB of RAM and a stripped pair of modern 7,200 or even 10,000 RPM SATA drives.

 

Thanks for all the replies upto now !!!
My actual processor is AMD Athlon Thunderbird 800mhz and RAM = 256 MB PC133 DIMM.
Both are most probably the main reason why multi-tasking is very poor on my actual computer.
After all, I bought this computer on 2000.09.28 and win2000pro is still my OS.

I'm planning to buy a complete NEW CASE with winXPproSP2 and I will have more RAM (2x1024MB) and two WD Raptor harddisks.
I also will buy AMD Athlon64 or AMD Athlon64 X2 Dual-Core, but I still have doubts. That's why I'm writing these posts
I admit, I made alot of mistakes with my actual computer, but I like to move on and alot of things changed during these 5 years, including me.

If I buy a single CPU :
AMD (939) ATX Athlon64 3800+ 512Kb Venice BOX (315 EURO)
I'm sure my computer will go alot faster, than ever before, but is it smart to buy a single CPU even when it's faster if you have multi-tasking in mind ?
Gaming or not, multi-tasking is always there.

I also can buy a dual CPU :
AMD (939) ATX Athlon 3800+ 64Bit X2 Dual-Core Processor (= 362 EURO)
and it costs only 47 EURO more.
Or I also can buy this :
AMD (939) ATX Athlon 4800+ 64Bit X2 Dual-Core Processor (= 862 EURO)
That's too expensive, but it will be cheaper in the next years, so I can upgrade later.

I don't have any problem with paying 47 EURO more and maybe even more, if it's worth to do it.
According Arup, who has practical experience with dual CPU's, it seems to be a good investment.
I would rather believe Arup, than what AMD is saying on its website, because there is sometimes a big difference between theoretical talk and practical experience.
I don't have any experience with dual CPU's, but I have alot of lesser good experiences with multi-tasking on single CPU's.
I don't expect a very fast processing from multi-tasking, but I don't like that other applications almost stop doing their job during multi-tasking and that's what I expect from a dual CPU.

It's not only about money, it's more about doing the right thing.
If a dual CPU is better for multi-tasking, than I prefer to buy that one,
but I like to hear this from other members with more experience.

 

You can also buy a dual CPU capable board but run a single dual core AMD 64 CPU in it, add another CPU when you have the extra money.

 

A main frame is designed for multiple users, the I/O to many users (Via terminals) and devices (hdd storage) is the biggest bottleneck.

The cpu spends an age in relative terms waiting for i/o operations on ANY computer.

So the main difference is main frames (against desktop pcs) can handle a lot more i/o from the difference users/devices and keep that cpu running at full capacity for as long as possible.

The main way of doing this was having the devices control themselves (eg scsi which causes massive I/O to hdd) off loading the processing of the i/o to the device instead of the cpu.
Eg my test server, the scsi card queues and optmises the order of requests, and also uses the 32mb interal cache for further optimisation, all operations with on IDE the main cpu would need to do and THEN send each i/o request one at a time to the device and wait for a response before continueing, whereas the SCSI card can do the waiting to let the main cpu carry on with an other task.

Take an early desktop pc, stick a multitasking OS on it (eg linux), run scsi drives and you are probably not far off a small scale main frame machine.

Bit of mainframe history from what I remember at uni (I used to play on a hp mainframe):

Main frames, the early main frames were batch job devices, user submitted a job via a terminal, it was put in a queue for the mainframe to churn through and return the results later.

Later main frames commonly are actually a distributed system (lots of machines linked together), exspandable with additional processing units (with 1 or more cpus on) and ram modules and upgradable storage arrays.

On a main frame there is a lot more I/O capacity; home PCs do relativly little i/o compared to processing, main frames need to handle a lot more i/o. This is usually done by being able to do multiple i/o operations at once to storage (ram and drives), shared paths is a term that you might hear crop up.

Also main frames will run a customised/optimised OS (AND hardware) for a specific application, for optimum performance AND security, eg running one database, they dont need the versitility of a desktop OS.

 

After reading all posts and AMD website, I'm going to buy
AMD (939) ATX Athlon 3800+ 64Bit X2 Dual-Core Processor (= 362 EURO) OR
AMD (939) ATX Athlon 4200+ 64Bit X2 Dual-Core Processor (= 447 EURO)
because that's the one I need to make multi-tasking even better.

together with :
Harddisk = WD Raptor 74gb 10000rpm SATA 8mb Cache 4.5ms and
RAM = DDR Value Dual Channel 2x1GB PC3200 400MHz

I assume that multi-tasking won't be a problem anymore.
I don't think I will have a slow computer this time.
Thank you for all the advices and info. Much appreciated by this hardware newbie.

 

Alec makes some very good observations about multi-tasking bottlenecks: particularly about RAM, drivers, and hard disk.

The problem is not in the OS these days as NT/XP seems to be very capable, but in the applications that aren't very well constructed to take advantage of either dual-cores or multi-processors, e.g. SMP.

Part of the reason is that the environment tools necessary to develop true multi-processing applications have not become well-known outside of multiprocessor companies and/or universities. Dual cores as I understand it is equivalent in processing power to two processors, or one dual chipped board with shared memory. Think in terms of quad or better boards with a large shared memory if you want a true multiprocessing experience - and good luck finding applications that can take advantage of the processing power.

Back in the day when I worked for such a multiprocessing company, circa '87-'88, with just a 10MHz Nat'l Semi chip and 18 processor boards, one could get near linear performance from our compiler runtime systems with all 18 allocated (dedicated) and less than a 1% locking collision rate when running massively tasked realtime applications (military) - i.e. many more tasks than processors available. The company's test-bed was the company's work force of about 126 folks, so we were used to very high-performance almost instant response from running any application (truly multiprocessed applications). I remember running the Gosling version of Emacs - didn't want all the fuss of having to learn Gnu Lisp at the time - you remember Gosling of Sun Java fame don't you - same one! All of the unix apps were multiprocessing versions - and a very nice parallel debugger to boot. Can't get that on Windows even today. Maybe when MS gets off their collective duff and gets Singularity - i.e. their new OS which is probably a derivative of Mach out the door to customers (much like a modified Mach which we were running) we might just see more of the capabilities for true multiprocessing make its way into the market place. Of course, we all know that ain't gonna happen none too soon.

Note1: Microsoft Research has developed a prototype of a microkernel operating system, code-named 'Singularity.' Its most surprising feature: It has nothing to do with Windows. See: http://www.microsoft-watch.com/article2/0,2180,1882174,00.asp

Note2: If you want to keep abreast of the latest technical innovations (happening every day), I strongly urge you to subscribe (free) to the newsletter of www.physorg.com Quantum computing, nanotechnology - WoW - and I don't mean World of Warcraft either!

-- Tom