Since iOS 5, Safari crashes have increased on both my iPad 1 and 2, but the crashes are significantly more frequent on iPad 1. There might be reasons other than RAM, but when I check my diagnostics logs on both iPads, RAM errors appear more frequently on iPad 1 than iPad 2.
Interesting to hear from someone who has both the iPad 1 and the iPad 2. It makes since that the iPad 1 has more memory issues as it has less RAM.