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When I used the music converter on a Pentium 4 3.0GHz which is hyperthreaded, it show 2 CPUs when the converter is doing it's thing. I just got an i7 920 which is Quad core hyperthreaded. I thought I'd see 8 cores on this box, but I only see 4. Is it possible to get 8? I have registered reference version.
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Re: multicpu support for HT
dBpoweramp currently is limited to 4 cores, even though if it did support 8 cores you would not see any improvements (IMHO), with HT, after all it is not a seperate core. -
Re: multicpu support for HT
Doesn't that assume the process is CPU bound (i.e., all 4 cores running 100%)?
Edit: Also, wouldn't that make the HT support in the Pentium 4 that I experience useless as well? It doesn't really make sense to support it sometimes.Last edited by psr6str; January 30, 2009, 04:11 PM.Comment
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Re: multicpu support for HT
AFAIK HT is much about cache invalidation and pipelining. Intel once said thre can be a 30% speed increase, yes if code is written just to show HT, reality will be lower than that.
I am not a believer in HT, I see it more marketing than delivering. Infact certain tests with HT, show it to be slower than not having it switched on:
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Re: multicpu support for HT
Well, you may be right, but that reference sure doesn't do much to convince me. The obvious reason being that it was written by their competitor who didn't have the technology at the time, but moreover this paragraph is very weak:
"Industry standard benchmark tests show that Hyper-Threading does not provide consistent performance benefits on real-world desktop applications. Enabling Hyper-Threading can even worsen a Pentium® 4 processor’s performance by as much as 10% on some applications."
It's generic and basically just says we can show some instances where it's not useful. That obviously doesn't mean it isn't useful the rest of the time... And I'm sure the general application space has come a long way since then to take advantage of it.
In any case, it's not that it doesn't support HT, because it actually does as proven by my P4. It just doesn't support more than 4 "cores" however they are defined. While I guess it doesn't matter too much, multi-cpu support was the primary reason I bought dBpoweramp reference over using other free tools, so my vote is for future 8x support.Comment
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Re: multicpu support for HT
My position is that, by default, dbpa should support as many real cores as there are on the system (e.g. 1, 2, 3, 4, 8, 16). There should also be the ability to limit the number of high-CPU usage threads used (e.g. parallel codec conversions) to a user selected number <= the number of cores.
In addition, the user should have the choice to allow each HT CPUs to be seen and treated as two CPUs, but a caveat should appear on screen that doing so may actually reduce performance. An additional caveat should also be shown that limited disk IO bandwidth and fragmentation can also significantly impact throughput, so consider limiting the number of threads/cores used.
In a perfect word, the suite would do all the above.
-brendanComment
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Re: multicpu support for HT
For a start, I'd take the default is to use all real cores and HT is enabled. If you wanted to default to all real cores and HT disabled (but can be enabled), I'd be fine with that too...after pushing the limit to 8 though. I can do simple time tests to see which way is better for me.
The reason this is important is for the mass conversions I do for my library - it takes hours and hours to do, so any speed increase is exciting.Comment
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