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jerryuscg

Proof that "Muli-cores" does NOT help FS2004

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As many of you have read todays news on AVSIM the info prooves to me that in fact multi core or multi CPU processors does NOT help FS2004. As the quote below states, WHEN the SP1 for FSX arrives, THEN the multi-Core Computers ( and Single cores when benifit). Here's the quote"On the day Intel Corporation introduced its Core

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Nothing whatsoever was "proved" by the press release, which is about FSX, not FS2004.Although there is a person or two with claims of terrific and direct improvement to FS9 performance with multi-CPU operation, I have yet to reproduce anything like it. But one thing is undeniable...multiple cores do help take other CPU overhead away and allow FS9 to run with less impact. For example, I can leave my antivirus running on my Core 2 Extreme PC with no visible impact to FS9.RegardsBob ScottATP IMEL Gulfstream II-III-IV-VSantiago de Chile

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Bob hit the nail on the head. I don't think Dual Core "improves" FS performance directly but I no longer see pauses when ASV updates for example. It offloads the background processes to the other core allowing FS to stay smooth. I would say that is the biggest advantage... It is almost like WideFS on a single box. Just running FS alone though I never see the second core doing anything it is just for the secondary processes and Windows itself which makes FS appear to work much better. I didn't see a "huge" performance jump from the single core FX-57 @ 3.0 to the Dual Core C2D at 3.2 gigs but like I said there are no more pauses even if there wasn't a huge FPS gain...BUT with that being said, FS9 was released PRIOR to Dual Core so unless MS wrote a patch we all missed to optimize a single core app across multiple cores I think it is pretty safe to say it is a single core app :)-PaulPrimary RigLiquid CooledIntel C2D E6600 @3.2 gigsAsus P5N32SLI-Plus2 gigs Corsair XMS PC6400 4 4 4 12 @810Dual OC'd XFX 8800GTX @ 2 gigs24 inch Widescreen LCD 16XAA/16XAFDual 19 inch LCD'sRaid-0+1PCPower and Cooling 1k Quad SLIhttp://home.comcast.net/~psolk/3monitorsa.htmlBackup RigAMD 4000 San Diego @ 2.72 Gigs Kingston Corsair XMS CL2XFX 7900 GTX Raid-0psolk.jpg

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Hum...I can only speak for FS9...Phil Taylor is talking about fine grain parallelization, wherea single process (calculation) is coded so it can run on multipleCPU. This is required to take advantage of the many core cpu that are are currently high end machines but will be commonplace.I have posted comments on the advantages of dual core and threading -this is coarse grain parallel code. How do I know that FS9 is threaded and can run on different CPU - 1) You get terrain blurries2) There is a setting in FS9.cfg that controls the terrain processor fraction. FIBER_FRAME_TIME_FRACTION=0.503) It is a graphics program and must use threads for the interface.4) Look at the CPU usage after you have out of a flight - youare not flying but look at that CPU. (indicative of but not conclusive evidence of multiple threads like 1 and 2)Try slewing to another point in the map, then continue to fly - youwill see that you are flying - but the terrain slowly catches up.In general, terrain "seams to have a life of its own and blurs". Thisis because it is a thread and not that same process as the "integrator"that allows you to fly. You can change the proportion of time givento the terrain engine (see 2), which improves the terrain loading, butdetracts from the fps (integrator). So why did Phil Taylor make this announcement...1) I don;t know if FSX uses the same terrain engine - I understandit does not suffer from blurries. Ie the next step in time for theairplane is integrated and all terrain is fetched for this frame ina single process - you will never get blurries - but you get badstutter if that terrain is still on disk since the integrator mustwait for disk load of terrain. As a thread it does not wait, butcatches up later in the separate thread. I have only tried the FSX demo and did not characterise it as I felt the FS9 was theway to go; any blurries at all then it must be a threaded2) There is an issue with cpu speed (mainly heat) that is holdingback on CPU performance;the simplest, and the way intel and AMDis going is to make multiple processor chips. With more than 2cpu the you very quickly loose the advantage of threads (ie there isonly so many threads, and any more CPU will not help) 3) An application (the whole of FS9) can suffer from coherence oF memory (look it up in wikipedia) so even if there are multiple threads you get no benefit with multiple CPU. This depends on the quality of the code.FS9 does appear to benefit from 2 cpu where the integrator andterrain engine + other minor threads can get 180% (where 200% isachieved by 2 cpu system where 1 cpu = 100%), of CPU. This doesdepend how you tweak your system. It is unlikely that FS9 will benefit from quad (or more) core machines as it only has coarse grain parallelization which is artifact of the way they did theterrain engine. It is not clear how many other threads there arewithin FS9, though I believe the root FS9.exe spawns the integratorand terrain engine, so is a root thread itself. The interface mustuse threads to detect events as it is an event driven interface. Finally, the computer will require non-fs9 processes to handle thevery heavy usage of the application - these processes will be seenas kernel processes. To really benefit from multi-core without knowledge of computingfor a user then the software vendor must write parallel code. Parallel code can be written in a number of ways, the easiest isto use a compiler that supports it then put in compiler directivesthat split a repetitive bit of code (ie loop) into multiplechunks depending on the number of available processors. Since MS provides FSX as exe and dll only, then they need only to buythe necessary compiler and put in simple directives in the codewhere there are bottle necks. Properly written parallel code can often give nearly linear speed upwith multiple CPU up to the point when coherence and data handshaking gives problems. Sorry, but a bad day at work (writing multiple threaded code). Sodoes this post matter - no not really - should I really care - no,but I couldn't face another hour writing mult dimensional data mining/visualisation tools. Just enjoy using the simulatorand trying not to think that the grass is greener on the other side.Tom

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Regardless of whether or not it utilizes both cores effectively (it doesn't) the dual core processors are still lightning fast overall and there's nothing out there pre dual core that will even come close for FS9, performance wise.That's the reality despite all the denial by some non dual core owners.

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