gjsmo said:
Well, just to get this straight - I DON'T want to do high-power
gaming. I want to offload most of the everyday graphics to the GPU
(and play some old games as well, which don't require much
horsepower). For example, today I was using Garageband '08. It often
takes a few seconds for the display to update when listening to songs
"live" (before mixdown to an AAC-encoded file). I think that's because
of my video card (am I wrong? I know more about software than hardware
- like I can program in C++, but couldn't tell you why anyone would
invent DDR2 then DDR3 and make all the slots incompatible (JUST RUN IT
AT A SLOWER SPEED!!!)). I run Playstation games, and that only makes
sense to run them at 720x480 (NTSC). Mostly, I want my GUI to be
faster, not my games (although that might be nice too...).
And if the Mobility version of the Radeon 9000 is just a mobile
desktop chip (I think it is, according to ATI/AMD) it's then I'll get
the 6200. Because that laptop doesn't work. And I'm on a low budget
right now. Seriously, I really think a 6200 is enough. And if I had
the money for a good graphics card, I would just go all out and get
myself a Mac Pro.
You need to look at a CPU performance chart, while Garageband is
running. If the CPU is running at 100% for those few seconds,
it could be that you're CPU bound. Or, if the computer is reading
data from disk, that could be the rate limiting step. (MacOSX has
good file caching - if the file was recently written to disk, the
unused memory in the computer also holds a copy. The copy in RAM
will be used on a read operation, if it is still valid.)
One of the things the video card does in MacOSX, is support
compositing. Each window is stored in the graphics card memory,
making it easier to move them around, support transparency and
the like. Microsoft does something similar with Aero on Vista,
where the graphics card supports desktop effects.
My experience on my PowerMac with 1.2GHz processor, was that
MacOSX sucked the life out of the increase in processor speed.
I went from an older machine running MacOS 9 at 500MHz, to the
newer machine. The new MacOSX at the time, made the machine
seem as slow as the old one. I booted into MacOS 9 on the new
machine and it felt pretty snappy (as this was the last Mac
that supported booting either OS -- it is the reason I bought it,
so I could use any software I wanted). I don't use that machine
much at all any more, and use the PC instead.
The day I bought it, I put 2GB of memory in it. Because I'd heard
ahead of the purchase, that the new OS needed plenty of memory.
I've never regretted putting the RAM in it. I could do all sorts
of things, like run the Mac version of VirtualPC, and have room
for it with the 2GB of memory.
I was kinda surprised at my graphics upgrade results, and that
going from the 9000 to the 9800Pro had so little effect. The
9000 seemed to work well enough for compositing, and I never
had any situations where I could conclude there wasn't enough
graphics memory on the video card. I think my computer really
needed to double the processor speed, to see a change in game
performance. Having to pull the 9800Pro back out of it, was
no big loss.
The thing about DDR, DDR2, DDR3 is easy to understand. In a
Powerpoint slide set presented at an industry trade show,
someone from a memory company said they needed to make a new
memory type every 2 years, in order to be able to charge more
for the new memory. Hardware prices decline with time, and
there is no profit to be made near the end of the two year
period. Thus, a new memory must be introduced, to prop up the
profit picture. Memory has had the interface speed increased
tremendously, so that a burst can come over the bus in a
shorter time, but the access time has not improved at quite
the same rate. And access time is important for computing
with no locality of reference (random memory accesses).
Moving arrays around with the computer might be faster
with the new memory, but the access time still is an issue
for programs with large memory footprints and relatively
random data access.
If you're a programmer, you understand the need for "profiling"
and performance analysis. See if there are any tools for the
Mac (because I don't remember right off hand), so that you can
at least monitor %CPU and disk activity. My Mac has no LEDs for
disk activity, so I cannot tell from looking at it, whether
the disk is being pounded. As for CPU, I can listen to the
sound of the system fan, and can tell from the sound of the
box, whether the processor is running at 100%.
Paul
