Below is a warning that I got when I attempted to upgrade my ubuntu from 12.04 to 12.10
I wish to upgrade because currently my screen brightness issue isn't resolved and I strongly feel it's due to the absence of a graphics driver (like Intel CedarView, which appears to be a driver meant only for the 32-bit version). The easy way out would be to upgrade but I get a warning as seen above.
My Question:
Would it be safe for me to go ahead with the upgrade or not?
It seems your graphics card has a problem with Unity in Ubuntu 12.10.
You have a few options:
I think the best option boot 12.10 on a live USB and test your hardware. If it works well, upgrade.
If unity is slow you might need to consider an alternate desktop such as k/x/lubuntu. Again testing before you upgrade is the way to go.
I also advise you make backups before you upgrade in case you do have a problem.