a relatively simple question on dual processor/core
- Thread starter richardyu301
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thanks! have not visit that site for a while. it looks like no major performance difference between them. i got three duel processor systems, intel's chip is just hot hot hot! amd is much better! looking to build a duel core mini system for the road. the single core chips just could not meet my performance requirements.
just the opposite.....
dual core cpu as well as the hyperthread functionality (if present), and that adds the new layer of complexity of Dual Core Hyper Threaded setups too....
these work irrespective of the operating system and do not need explicit configuration by either the applications running on them nor the operating system running on them...
picture in your mind a train station platform that is wide enough to handle 4 persons walking side/side as they get on and off the train....
now picture same train station with a platform wide enough to handle eight persons walking side/side as they get on and off the train....
in both scenarios, neither the persons in transit (applications running) nor the train (operating system) needed to be reconfigured to take advantage of the higher density platform...
(meant for illustrative purposes only)
Acutally, the operating system implementation and optimization makes a big difference on the impact of dual-core and hyperthreading performance.
Hyper-Threading is the culprit here. The Extreme Edition class of processors have Hyper-Threading to allow them to execute four threads consecutively (on four logical processors, but there are only two real physical cores). The Pentium D class processors on the other hand, have no Hyper-Threading, limiting them to two threads for simultaneous execution on the two real physical cores. Now what happens on the Extreme Edition processor is that that operating system is unable to cleverly dispatch the threads to the right logical core. For example, if two threads are being issued to two logical cores that belong to the same core, the processor's equivalent operating speed is as good as back to a single core Pentium 4 with Hyper-Threading.
This only goes to show that Hyper-Threading isn't really your best ally in all cases though it was a great idea to use unused processor resources. The current generation of processors is probably the last of them to feature Hyper-Threading as Intel's forthcoming Core 2 Duo processors will no longer have it and looking even further ahead, Intel is going to employ multiple cores instead.
The underlying hardware in a computer system is only as good as the software - i.e. the Operating System has to be optimized to take advantage of the unique hardware features. Yes, an unoptimized OS will still work in these situations, but to make real use of dual-core and/or hyper-threading performance advantages, the OS has to be optimized for it (similar to when a compiler is optimized to take advantage of specific hardware).
In your analogy, 4 people walking side-by-side on a platform requires a narrower entrance into the train (operating system). If you want to take advantage of the platform big enough to allow 8 people side-by-side, then you need to expand the entrance to the train compartments - because if you don't, only 4 people will be able to enter the train simultaneously even though the platform allows 8 people.
Hyper-Threading is the culprit here. The Extreme Edition class of processors have Hyper-Threading to allow them to execute four threads consecutively (on four logical processors, but there are only two real physical cores). The Pentium D class processors on the other hand, have no Hyper-Threading, limiting them to two threads for simultaneous execution on the two real physical cores. Now what happens on the Extreme Edition processor is that that operating system is unable to cleverly dispatch the threads to the right logical core. For example, if two threads are being issued to two logical cores that belong to the same core, the processor's equivalent operating speed is as good as back to a single core Pentium 4 with Hyper-Threading.
This only goes to show that Hyper-Threading isn't really your best ally in all cases though it was a great idea to use unused processor resources. The current generation of processors is probably the last of them to feature Hyper-Threading as Intel's forthcoming Core 2 Duo processors will no longer have it and looking even further ahead, Intel is going to employ multiple cores instead.
The underlying hardware in a computer system is only as good as the software - i.e. the Operating System has to be optimized to take advantage of the unique hardware features. Yes, an unoptimized OS will still work in these situations, but to make real use of dual-core and/or hyper-threading performance advantages, the OS has to be optimized for it (similar to when a compiler is optimized to take advantage of specific hardware).
In your analogy, 4 people walking side-by-side on a platform requires a narrower entrance into the train (operating system). If you want to take advantage of the platform big enough to allow 8 people side-by-side, then you need to expand the entrance to the train compartments - because if you don't, only 4 people will be able to enter the train simultaneously even though the platform allows 8 people.
It all depends on how you use your machine.
This is similar to the idea of do you partition your hard disk or not?
Similarly, how much CPU is your biggest single thread using? If it is 90% and the rest takes 10% then you may be better off with a single CPU.
If on the other hand your biggest CPU demand by a single thread is something like 50% then yes, by all means, a dual core will benefit.
We did tests and found that TradeStation 2000i benefits significantly by using dual core. BUT...we had to assing one process to one CPU (Global Server) and the other to the other CPU (TradeStation itself).
(there is free software available on the web where you can preset which CPU to use for a particular piece of software. You can even permanently change the affinity of the software for a CPU....)
Just be aware that the dual core CPU's are not running yet at the same speed as the higher speeds single core.
The differences in performance is these days not as great as in days gone by. (in the old days it was quite commong that a new machine would run several magnitudes faster than a machine that was a high end machine a year - 18 months prior.)
We had to search very hard to find a laptop with double the performance of our high end laptops that we bought 3 years ago (!). (These were at the time the highest spec'd laptops that we could find. Desktops are another matter).
Maria
jaytsecan,
You sum it up very nicely! Thank you.