I’m just curious!
Honestly, all other things being equal, an UCI graduate has the same chance of getting into a grad school as a Purdue graduate. The difference would come in the letters of recommendation. If a professor that writes your letter of rec whom you did research with as an undergrad is known to a professor at the graduate school you apply to you will be more likely to get into the program. No graduate school is going to accept/deny you just because you went to a certain school.
Based on your other posts, it looks like you are considering their CS programs.
While its great that you are thinking about graduate school now, I don’t think need to. Specifically with CS, a graduate degree isn’t really necessary. Most of my friends working in software don’t have a masters degree or PhD. And those who do, have one because they either switched fields into CS, did a 4+1 program at their undergraduate university, or did it as a way to immigrate to the US.
If you really want to get a graduate degree, I’d recommend looking into a 4+1 program where you take an extra year after you finish your bachelor’s degree to get a masters degree from the same university. The CS department should have information about this if they offer it.