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Discussion Starter · #1 ·
64 bit processors have been around for a long time, and ditto Linux support for them. However, due to price and specific processor support issues in software, recent availability of 64 bit processors which support legacy (often lower-end) instruction sets & CPU families supported by unported software has made me interested in this question anew, specifically for the various CPU-intensive applications that may and/or do happen in a HTPC, in Linux, and perhaps in other OSs.


Since the legacy software (and software that is being programmed as if it is legacy software) has to have at least some support for these "new" 64 bit CPU options (even if by luck through various already compatible library functions), and since various algorithms respond differently to CPU features, these questions are pertinent.


How much do 64 bit processors help?


What about the various 64 bit AMD processors and motherboards available? E.g., Opteron & the new Athlon 64 line.


What about other types of processors?


Which software does it help with? E.g., converting an HDTV MPEG2 highest quality stream to best fit and quality on an NTSC output (tvtime?), and converting HDTV MPEG2 highest quality stream to highest quality best compression algorithm (MPEG4/DivX).


What software can be recompiled to achieve these better results?


What source-available software can we compile ourselves to achieve this better performance, and what software are we bound against using due to source not being available?


What software requires simple updates to be able to achieve 64 bit utility? What software requires more substantial and/or comprehensive programming to achieve this?


Finally, while digging around attempting to create an idea of an inexpensive HTPC box that will basically do the functions I mentioned above (with the intent of obtaining about two to four such things), I wondered if there are any multiprocessor (MP) options that could help me with the following:


* Feature price performance scalability over time

* Price reduction of target features

* Allow otherwise impractical features


E.g., would tvtime/dscaler/divx be able to use a substantial amount of multiple processors during single operations? Is this theoretically possible? How much programming would be involved?


I assume multiple unrelated processes in the same box would be able to use MP nicely; is this correct? Do we have to use special invocations to achieve proper processor assignment by the kernel or whatever?


I already searched some places and did not find answers to the above questions, however, I did see a a web page with substantial performance increase benchmarks for Linux sound conversion in AMD 64 bit ( [remove spaces in URLs; can't edit them out in post#1] showing 34% improvement in the same processor) and another with Microsoft based MPEG2->MPEG4(DivX) transcoding in MP ( showing ~20% improvement against dissimilar available options), so I am very excited to see what real and fairly likely theoretical results you have/expect for Linux video applications.


Obviously, if I had more money, I could answer these questions by doing more myself.


Thank you.
 

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For a single app you mentioned such as tvtime/dscaler etc, I dont think multiple CPUs will do much for you except let you do more than one thing at a time. As for 64 bit CPUs, it still cracks me up that everyone is so gungho about them for today's software. It's great that you have a bigger address space in various ways but while the new 64 bit amd64 chips are showing performance improvements in various apps, it has nothing to do with the 64 bit-ness of the chip, its due to other improvements in the processors design. For a HTPC, I think it would be silly to spend 600+ on a CPU. If cost were not an object then hell go with a FX51. I think for what you are looking to do however Windoze would likely be a better choice than Linux at this point and the 64 bit win code is still in beta, never mind when we'll see apps that can use all the extra address space. For encoding video and audio I'd go with a fast P4 since it seems most encoding software is optimized better for them. If you'r elooking forward thinking that you'll hop on the 64 bit bus now, I don't think we'll see anything useful in 64 bit land for another 1-2 years and honestly many people upgrade their machines in that length of timeframe so what's the point?

-Trouble
 

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Discussion Starter · #3 ·
So far, that's my feeling, but I wasn't sure.


I think I need an Intel P4 2.60C for what I want

(800MHz FSB, 2.6GHz), and PriceWatch.Com lists them for $194.


I'm still researching a bit more before I post a big post asking what people think for the first setup I'm going to get. I just posted that 64bit question to dispense with it since it seemed like an easy question that won't effect my decisions much since I doubt it would have been useful for my case, as you pointed out, but it's a fine point of reference for me.


I find it interesting that the recompilation accesses those non-64 bit features you mentioned.
 

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Hello,


when money is not the big point then get as much power as you can.


If you want to use ffdshow filters you need every piece of power you can get. If you want to use the filters of mplayer (unsharp mask, denoise...) you even more power.


Which processor is hard to decide. If you want to have a pure HTPC perhaps it's better to take a Pentium 4. You find special benchmarks to get an overview over video related tasks in the Link above. The article is in german but the graphics are easy to understand. Go from the main page to the right "Inhalt" (contend) and select "video encoding" or whatever you want. It's one of the "biggest" tests I know about the Athlon 64.


The Link is here


For unknown reason I cannot produce a direct link the the benchmarks.
 
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