Will a New Dell Latitude Z be faster than my Sony Vaio????

I have a Sony Vaio VGN-Z690 with a Intel Core 2 P9600 (2.66 GHZ; 6 MB Cache; & 4 GB RAM) and I'm thinking of going to a new Dell Latitude Z (company provides) which has a Intel Core 2 SU9600 (1.6 GHZ; 3MB Cache; & 4 GB RAM). The new Z would have a SSD over the converntional drive in the Vaio. My use is exlusively business apps: Word, Excel, Outlook, General Inernet browsing; light photo editing and management. And I use Skype extensively with video calls when traveling. I'm worried about the new Z being overall slower in the apps to the point of being very noticible. But on the other hand, the newer chip, the SSD, etc., I would hope, would make the new Latitude Z as fast or faster. Any comments or thoughts as to alleviate or confirm my worries is appreciated; hence, which is faster? Thanks.