[mss1337]

I never do any sort of photoshop or video editing work. What advantages (beyond gaming) does having the more powerful gpu confer outside of photoshop and video editing. Does it improve HD video playback? Does it make the OS run better? Or is there no real difference between in terms of performance the 128 and 256 versions?

[riotge@r]

There is no real benefit in having the extra RAM for general computing within Tiger. You may see a benefit when playing large HD video files and the next Apple OS may also take advantage of 256MB of RAM.

[mss1337]

So you are saying that if you play a quicktime vid at 1080p, the gfx (256) card is a doing a lot of work and if you had a lesser gfx card (128) it would drop a lot more frames?

[mduell]

First you say "more powerful GPU" but at the end you say "between the 128 and 256MB versions"; are you asking to compare between an older slower GPU and the current CPU, or between the 128 and 256MB versions of the current GPU?

Either way, no change in Photoshop performance. Video editing performance may improve in both cases, depending on what apps you're using and how hard you're pushing them. The newer GPU (but not more VRAM) may help in the future with HD video playback, if Apple ever adds support in their video driver for that. The OS will run just the same.

Originally Posted by riotge@r

You may see a benefit when playing large HD video files

Do you have any evidence to back this assertion?

[Barefoot Matt]

Originally Posted by mduell

Do you have any evidence to back this assertion?

One thing I find interesting is that the system requirements for playing 1080p videos include more VRAM than those for 720p videos, which would suggest that the VRAM is somehow useful for processing such videos.
http://www.apple.com/quicktime/guide...endations.html

[aristotles]

You will see no difference between a 128MB or 256 MB gfx card when playing back video. A 128MB card is more than enough. What determines dropping of frames is your system CPU speed and your current load.

[mss1337]

Sorry for being vague, but what I meant what is the difference between the two graphics cards in the two MBP versions. Also, what are the benefits of having the 256 version.

[photoeditor]

No difference between the two graphics cards -- they are both X1600 Radeon Mobility cards.

I also have questions on the 256 version and I will be very specific here . . .

1. Core Image. Does 256 boost you on something like Aperture with lots of open images?
2. Gaming. Does the deeper frame buffer help framerates in any non-gorefest, non-horror kind of 3D game?

Also an observation. I noticed that MacWorld's benchmarks on the new iMac for Doom 3 (talking of gorefests) show 27fps on the 1.83GHz and almost 36 on the 2. They CLAIM to have had 128MB VRAM in both, but I can't see how that is possible with such a large performance difference between the two models. What is going on, and might it help us answer the question of whether VRAM would make a difference on the MacBook?

[photoeditor]

Hmm -- surprised there are no further responses on this.

Anyway, I encourage you all to take a look at BareFeats' latest benchmarks on the MBP and iMac. It sure looks as though the speed advantage on the desktop X1600 for the iMac beats the VRAM advantage on the MacBook for gaming and even just about ties the MacBook on the purely Core Image test of Imaginator.

It is beginning to look as if the purpose of 256MB of VRAM on this chip is solely for 2D pixels, or screen "real estate" as everyone likes to put it -- either in the form of having lots of windows open such as with photo editing in Nikon Capture, or having a dual display setup between both the MBP and at least a 23 inch Cinema Display. Otherwise, I suspect the extra VRAM is completely redundant. The Mobility X1600 doesn't seem to me to have the juice in terms of pixel pipelines and clockspeed to use 256MB of VRAM on 3D. That's not too surprising in view of the specs, but it is useful to see it in reality.

And, as suggested by most of the earlier posts in this thread, no significant video benefit to the larger VRAM either.

I think it also bears checking whether or not the 1.83GHz iMac has the Radeon desktop or Mobility Radeon. Obviously the 2GHz iMac has the desktop version. That's the only remaining idea I have that explains the tremendous difference in the Macworld test I mentioned above.

[inkhead]

Where can you get the 256mb version? I didn't even see it in the custom built. On the 1.83 with 128mb video card + 512mb RAM only all the 1080p trailers play flawlessly EVEN the ones that have fast transitions.

[photoeditor]

256MB is a BTO option on the 2GHz iMac.

[Yutuke]

Hello,

1.8 vs 2.0ghz FPS difference
Yes, all things being equal, the difference in CPU speed is going to show a slight increase of frames-per-second in a game like Doom3. The CPU is involved in doing all kinds of calculations (phyics, collision detection, etc) so every little bit helps.

128mb vs 256mb video cards
Depending on the application or game, yes, more VRAM can help. Sometimes games use your main memory to store large textures. When it doesn't have the room to the texture in VRAM then it might use your main ram to store it. Then when it needs it, it makes some room in VRAM (by some magical scheme the programmer digs up) and copies the texture from main ram to VRAM. This texture swapping is the same thing as the virtual ram that OS's use. That copy can be slow depending on bus speeds, etc.

If the game you buy REQUIRES 256mb, then of course you are out of luck if you are stuck with 128mb.

Programmers can always use the extra memory to do frame buffer tricks and texture processing. You can never have too much memory right?

Will applications like Aperature use this ram? Maybe. I don't know all the internal workings of OS X but since the OS is video accelerated in nature then it probably does make a small difference but nothing that the average user is ever going to notice.

Thanks.