Question on multi-core CPU's

By mharper
May 21, 2007
  1. I have read that most software today is not written to take advantage of multi-core CPU's (i.e. is not vector based or does not have independent modules). Therefore, a program running on a single core CPU at a higher clock speed may be faster than running it on a dual core CPU at a lower clock speed even though the theoretical throughput of the dual core CPU is higher. This makes sense to me.

    My question is will CPU intensive tasks (like rendering a DVD) occupy one core on a dual core CPU leaving the other core available to do something else? Or since both cores share the same bus for I/O will the I/0 create the bottleneck? Given the state of software now is the multi-core CPU really worth the extra expense?

    Thanks in advance for your thoughts.
  2. Rage_3K_Moiz

    Rage_3K_Moiz Sith Lord Posts: 5,431   +28

    According to what I know, both cores will be used dynamically but you can set the program to use one core by setting its affinity from Task Manager. Future programs will take advantage of multiple cores so they are worth it in the long run.
  3. Tedster

    Tedster Techspot old timer..... Posts: 6,000   +15

    It really depends on the software. most anti-virus programs and some cd/dvd burning programs are multi-thread/core programs. Games in general are written for single cores. While the clock speed between and single core is small - say a few hertz, most won't notice the difference.
  4. Nodsu

    Nodsu TS Rookie Posts: 5,837   +6

    All modern operating systems support multiple cores and since you are always running many processes, they will be distributed evenly across the cores.

    Yes, a CPU-intensive single-threaded process will hog only one of the cores, leaving rest of the processes to the other. The IO bottleneck is a non-issue. Having two processes struggling for a data channel is still better than a single process getting a piece, then a pause when contexts are switched, another process getting a piece, more pause since the other process doesn't actually need any IO, pause for a context switch, etc.
  5. luvhuffer

    luvhuffer TechSpot Paladin Posts: 443

    I went from a P4 to an E6400. I can't get technical but when editing a large graphic file say a 2448x2816 the dual core is about 60-80% faster. When encoding an mp3 file, what used to take 2 or 3 minutes, now takes less than 1. The P4 was a 2.8 running at 3.2GHz. The E6400 is a 2.1 running at 3.0GHz. Of course I have the speed throttling disabled so it runs full tilt at all times, where with stock settings it varies between the stock and overclocked speed adjusting it as needed. So in some underintensive tasks, I would think it would run or seem to run a bit slower as the speed would be throttled back. If your question is asked because you're thinking of upgrading to dual core, I'd say yes. Go for it. The overall performance is much better than with the P4
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