XP/Vista dual system sharing file optimization

Everyone tried Vista, also saw, Vista default installation size is 7G to 8G, and XP default installation size is 800MB to 1G. More than several times XP, and the speed is the slightest Not surpassing XP, and our great Microsoft predicts that Vista will be twice as popular as XP. Why can't speed be twice that of XP?

I installed Vista with a partition size of 9.88G, and installed Vista after partitioning. There is only 1.xG left. How can this be done? Because XP is also installed, I have partially optimized the two systems by referring to the previous practice:

1. Sharing the TEMP temporary folder

2, shared page file

3, share favorites

4, delete restore

5, delete, sleep

out After the end, Vista's partition has nearly 4G of space left, still too little (greedy?)

PS: can not share the shared IE temporary folder, the names of the folders of the two systems are not the same, can not be changed, still Didn’t figure out how to share, if you have a good way, remember Oh my!