In Raw processor performance, the T7500 (2.2Ghz SR) will smoke the SU9600 (1.6Ghz).
Geekbench scores are almost 1000 pts apart.
The Graphics card on your SR MBP is also gonna be more powerful (the 8600M beats the 320M - discrete vs. integrated).
But depending on what you use the laptop for... it may not "feel" that different. Does your 2.2Ghz SR MBP have 2gb of RAM? Or 4GB? Do you do much more than surfing/youtube/email?
The 11" Ultimate is only $1399 USD vs. the 13" Ultimate being $1799 so that's a consideration I'm sure.
Again, I'll ask whether you need the smaller size, or are just looking for an upgrade? Is your 2.2Ghs SR MBP feeling sluggish? 'Cause an SSD and a RAM upgrade will probably breathe *years* of new life into it. And cost ~$300 instead of ~$1400+
fyrefly thanks for your reply. My 2.2GHz SR MBP has the standard-issue 2GB of RAM, but with an upgraded 160GB hard drive. It feels a little sluggish these days here and there, but it's also showing early signs of a possible graphics card failure (surprise).
Honestly, I just use this for Safari, iChat, Word, iTunes, iCal, Apple Mail, and occasional iPhoto, PowerPoint, and Excel. While I do appreciate the 1440x900 15" screen (prior to this, I came from a 17" PB), it's becoming really tiresome lugging this in my backpack to classes everyday.
The pricing difference between the 11" Ultimate and the 13" Ultimate is not a factor here; I'm willing to pay for whatever will be the better machine in the long run. I'm absolutely smitten with the portability and looks of the 11", but again I'm concerned that performance-wise it will be a step down from this soon-to-be 4 year old MBP- which I already consider past its performance prime.
And whatever replaces this machine will be my primary (and only) computer. Hence my slight wariness towards the 11".