virtual memory

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Postby jbone » Sun Jul 07, 2002 2:03 pm

mofisto wrote:As for Dual CPU, that does speed up your editing, because while 1 cpu is working on the OS the other can work on the editing. On threaded OSes like Linux and what not, it can turn a 2hour render into 1 - 1.5 hour, a small improvement, but worth it is you are serious about editing.


Wow, Mofisto. I didn't think it was possible for <I>anyone</I> to <I>so</I> misunderstand the <I>incredibly</I> simple statement that "a dual CPU system has NO bearing WHATSOEVER on memory." :-D
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Postby mofisto » Mon Jul 08, 2002 6:55 am

Not every piece of hardware on a computer is DMA capable. If its not, then the CPU sends instructions to memory. HENCE your system bus speeds. So there for, CPU does effect memory. You cannot get the same performance out of a 486dx with 256mb of memory as you could with a dual athalon MP running at 1.2ghz each. Aside from the fact that 486dx processors aren't using the same type of memory. The faster your CPU can write to memory and get back to processing, the more speed you will notice.

SO therefore your statement about a simple statement is incorrect.
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Postby jbone » Mon Jul 08, 2002 12:46 pm

mofisto wrote:Not every piece of hardware on a computer is DMA capable. If its not, then the CPU sends instructions to memory. HENCE your system bus speeds. So there for, CPU does effect memory. You cannot get the same performance out of a 486dx with 256mb of memory as you could with a dual athalon MP running at 1.2ghz each. Aside from the fact that 486dx processors aren't using the same type of memory. The faster your CPU can write to memory and get back to processing, the more speed you will notice.

SO therefore your statement about a simple statement is incorrect.


Your example demonstrates that you <I>still</I> have no idea what I'm talking about.

<I>I am not talking about performance. I am talking about quantity.</I> If someone has 384MB of RAM and, at a given instant, 497MB of data wants to go into RAM, you can stick in 64 CPUs for all you want, <I>you will not be able to get more than 384MB of data into physical memory.</I>

Oh, and you misspelled "therefore."
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Postby FirestormXIII » Tue Jul 09, 2002 7:00 pm

jbone wrote:Oh, and you misspelled "therefore."


You make me laugh with the strangest things jbone.
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Postby jbone » Tue Jul 09, 2002 7:55 pm

FirestormXIII wrote:
jbone wrote:Oh, and you misspelled "therefore."


You make me laugh with the strangest things jbone.


I try. :-D
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i'll throw my 2cents into here

Postby mckeed » Wed Jul 10, 2002 2:20 pm

me and jbone were jsut discussing this last night as i was having some virtual memory issues. first of all....if you use premire, use all the swap space you can.....in win2k, which i use you can set your limit to 4045 MB i believe. I keep my lower limt at 768MB. I don't have a shabby comp. I got a 1.33ghz athlon with 512 mb of 2100 DDR memory and a 180 GB stripped RAID array and a 30 GB 7200 ATA 100 drive for system stuff. When working with VOB's and each one is hitting a gig a piece, what virtual memory will allow for you is to open a few clips at a time and not have your system laugh at you or perform verry slow. Since with VOB editing you are running a frame server, it helps to be able to cache all the information related to frame positions and so forth with your virtual memory which is nice when you are working from a few different episodes, same goes with normal editing if you are working with large clips, as i will cache a lot of that inofmation so it doesn't have to re-determine it such as location of keyframes etc. The larger the swap file, the more information you can store and not have to throw out. Every programer knows that it is much easier to read information instead of derive it every time you want to use it. That is what virtual memory is used for. Even though it is slower than RAM by a whole lot, it is quicker than trying to use system resources to redetermine information that is allready in your swap file on your hard drive. When editing, you really should be using two hard drives anyway, one for system so you can allocate more swap space and not have the hard drive that you are using to read or capture your clips from being accessed by the system while you are trying to capture or just read the video files from. This might not matter when you are using smaller files sizes, but when you are working with large files it helps a whole lot. For optimal swap performance, you should have your swap file on a HD that isn't being used for system or storage of the clips you will be using. But it never hurts to have a large swap file. It all really depends on the type of demands you are putting on your system weather having a large swap file will actually make a difference to you.
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Postby mofisto » Thu Jul 11, 2002 1:20 pm

Okay, apparently jbone and I are on two different thoughts. Each of which is correct. When I read the original post:

How do I increase my virtual memory? I want to dedicate 12-20 gigs of space on my D drive for virtual memory. Can anyone help me?

I interpreted it as meaning he wanted to improve system performance. And the statement about using 12-20gigs, was insane. Thats what I am talking about. I repeatedly stated that I DO use virtual memory and I DO recommend changing the settings yourself. But the system performance is basically negligible. I completely understand that if you only have 128mb of ram, thats all you can use. But adding virtual memory, in the amount originally posted, just doesn't do anything but waste hard drive space, even if its not being used.

As for CPU not having anything to do with memory, I still disagree. The faster(newer) the CPU, the faster it can move between memory and write and recall from memory. The way I see it is that with a fast CPU with the system bus up there like RAMBUS speeds, you will access memory faster and the data will be in and out of there and on to the next set of data before virtual memory can finish.

But If jbone wishes to once again correct me that is fine. He probably does know more then me, which is also fine. I really don't care, I am done now..

Thanks in advance.[/quote]
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Postby jbone » Thu Jul 11, 2002 2:56 pm

mofisto wrote:As for CPU not having anything to do with memory, I still disagree. The faster(newer) the CPU, the faster it can move between memory and write and recall from memory. The way I see it is that with a fast CPU with the system bus up there like RAMBUS speeds, you will access memory faster and the data will be in and out of there and on to the next set of data before virtual memory can finish.
[/quote]

No matter how you look at it, 537MB of data can't fit into 448MB of RAM. :-D

Doesn't matter if the RAM is running at 100MHz or 100THz, or if there's one CPU or 1000.
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