Raises were completely divorced from any performance assessment. You were paid whatever they thought the max was for your skillset, based on a bunch of data they had on what people at other companies got paid for similar work.
What we did have was 360 reviews once a year. It was basically a small survey you could fill out about anyone in the company, which they and their manager would see. You could evaluate your boss, your VP, or people who worked for you, or anyone else you worked with anywhere in the company. It was expected that managers do a 360 review for all of their reports, but beyond that you could do as few or as many as you wanted to. It was basically a start/stop/continue kind of thing.
It was such a refreshing change from the stack ranking at eBay, which forced good people to get shitty reviews just so they could "fit the bell curve". And as you said, it incentivized you to not praise coworkers and some people even actively sabotaged their coworkers to get a better rank.