Since main thing to decode video is the main processor. Theoretically there shouldn't be any difference in power running 13" Vs. 15" MacBook Pro
The highest 13" now is: 2.53GHz Intel Core 2 Duo
And the lowest 15" is also: 2.53GHz Intel Core 2 Duo
13" has nVidia 9400 (256MB shared memory)
15" has Nvidia 9400 + 9600 (256 dedicated memory)
So only difference between two is that 15" has option for dedicated memory of 256, which is same amount of memory capacity as shared. What is so different if we have more than enough ram to share with the graphic processor anyway?

The graphics processor on the 15" is faster and has dedicated memory. That makes all the difference in the world when you want to use the VSL plug-in, all of the current effects...and the effects that are coming.

So you saying 256MB dedicated is so hugely more efficient than 256MB shared memory, even there is more than enough RAM?

doesn't seem like much of a difference on paper.......we could analyze specs all day but IMO i think the only way to come to a reasonable conclusion is to do a side by side (real world) comparison and see how each machine performs under VSL min med max settings.

There is a difference. I've used both and the 9400+9600 combo is much faster and stable.

The relevant difference has little to do with amount of RAM.

The 9400 is an "integrated" type graphics card that shares main system RAM. It's better-performing than the older generations of integrated graphics, but still lower-performance than a dedicated graphics processor with it's own RAM.

Part of the difference is that a "non-integrated" GPU is able to access its memory much faster, since that memory is "hardwired" to the GPU and not accessed over the main system memory bus. And also a dedicated GPU takes some load off the main CPU for certain video uses (such as mixing videos with Video-SL, for one example).

If you have any intention of using Final Cut Pro, you will be a lot happier and more efficient using it with a fast dedicated GPU.

DJ Pimp, DJ Mark said it best as to the differences.

Bottom line, you will have a much better experience getting the 15" vs the 13"

i think the screen real estate of the 15 is better too for doing vsl

store.apple.com

About 2 inches.

I don't need a new MBP. I have the 2.8GHz one, just I prefer smaller laptops.
When I got my 1st Serato back in 2005 I had a 7" Toshiba and people still thought that I am still on real vinyl back then.
It's just that idea of 13" MBP crossed my mind and wanted to discuss.
So actually I could try my 15" MBP by running only 9400 card to see how it performs.

i have the 13 inch macbook pro 2.26 ghz that i have as backup, haven't used it to do video, but will do so this weekend & get back to you on sunday about how well/not so well it worked

I currently use the 13" MBP 2.26ghz..with 4GB ram and run VSL SMOOTHLY...

I do an online radio show every week and I have ALOT running during my show.. SSL, Mix Emergency, iChat, Skype, Ustream, Camtwist....and I have noooo problems....

when i'm at gigs, I don't experience any slowdown or anything either and i'm just using SSL & Mix Emergency....

What DJ Shy did not tell you was.... He never see's slow down cause he is always dancing with some girl in the DJ Booth. hahaha

eloy.....not true.....wait......damn..yeah...lol

haha