Roger Buchanan said:
I'm figuring out what kind of parts I need to get, but could use some
help. The last system that I worked on building was a, ahem..., P-75...
<weak grin> Lots has changed since then...
I want to build a system for editing home video type things.
So far I know I want a motherboard with 800mhz FSB, Dual Channel Memory,
Intel chipset, NO integrated video/audio, SATA capable and able to run 4
or more Gigs of RAM. I'm not looking to overclock anything, or do any
"tweaks". Just want reliable and reasonable performance right outta the
box.
What other requirements should I be looking for???
Thanks in advance.
I guess my first question would be whether a video editing program
can actually use all that RAM. Perhaps Photoshop could make use
of it, for very large images at high DPI, but I would think that
video simply wouldn't benefit. I mean, if you had enough RAM, at
some point you could hold the entire clip in memory, but how much
memory would it take to hold a couple hours of video ? At some point
the video is staged on a disk, for input or output, and there
really isn't any advantage to holding a lot of the clip in memory.
First, you should do some checking as how much RAM people buy, for
use with the same video editing suite you plan on using. Maybe you'll
find that 1GB is enough not to limit performance.
There are limits to both program design and OS design, as to how
much memory an individual program can use, and what the split is
between the OS and userland. For example, with no modifications,
your average OS would give 2GB OS and 2GB programs. With a command
line switch, some can be convinced to do 1GB OS and 3GB programs.
Then the program itself has to be compiled to handle a 3GB space
instead of 2GB.
The bottom half of this post is where I learned about some of this:
http://groups.google.com/[email protected]
In terms of motherboards, the P4C800/P4P800 use 875/865 chipsets, and
have four DIMM slots, for using 4GB of memory. But, the PCI and AGP
devices need some address space, in order for the processor to access
them, and this address space comes at the expense of main memory. You
lose a portion of main memory as a result. Typically, you might see
3.5GB of memory available, when plugging in four 1GB DIMMs.
The latest series of motherboards P5xxx, use the 925/915 chipsets.
These also have four DIMM slots, and depending on the motherboard,
use DDR or DDR2 memory. They have the same issue with memory space,
but because the boards now include PCI Express card slots, even
more address space is wasted, at the expense of main memory. Using
four 1GB DIMMs, you might see 3.0GB of memory available.
See section 2.2.1 of these two Intel motherboard manuals, for details
on where the numbers come from:
ftp://download.intel.com/design/motherbd/bz/C3176501.pdf
ftp://download.intel.com/design/motherbd/cv/C6859701.pdf
In terms of performance, you might be thinking that buying 2x1GB
plus 2x512MB DIMMs would be the right solution. If you do that, you
can lose 20% memory bandwidth compared to 4x1GB DIMMs. So, depending
on whether this computer is for a home business, the economics of
your time might dictate buying the more expensive memory
configuration, even if some of it is thrown away. This was detailed
in an Anandtech article:
http://www.anandtech.com/memory/showdoc.aspx?i=1839&p=6
If this is a home business, you might also consider hardware
acceleration for video editing. The main benefit of acceleration
hardware, is it can do format conversion for the output process,
so you aren't limited by the performance of the processor for
whatever form of compression the format uses. The hardware is
also capable of doing some acceleration for simple transitions,
but many of the effects also rely on the processor for assistance,
so you don't get complete hardware acceleration. These cards can
be expensive, like $3000+, but if you are serious about your
platform design, might be work looking into.
http://www.canopus.us/US/products/Index/product_index.asp (DVRex)
There are also some drool worthy motherboards on the following
web sites, but it may be hard to take advantage of them for other
than server type applications. The software would be the limitation
here:
http://www.tyan.com/l_chinese/products/html/matrix.html
http://www.supermicro.com/products/motherboard/matrix/
HTH,
Paul