3% or less - the class action against Gateway long ago
Gateway advertised several models of 486 systems as "Pentium Ready", because Intel had designed a Pentium "Overdrive" CPU with a Socket 3 pinout, a superset of the pin signals used by a plain old 486. Lo and behold, Micronics built oodles of motherboards for Gateway and somehow missed out an an important design detail. These Socket 3 Pentium OverDrives would work well only in a motherboard that had a write-through external cache, but the processor itself had a more aggressive and less stable internal write-back cache. This was back in the day when CPUs did not have much built-in cache memory, and motherboards were populated with cache chips manually inserted into sockets. So put a Pentium OverDrive into a Micronics/Gateway motherboard, and the system would turn into a slug. Back in these early days, bus-mastering controllers like SCSI host adapters would not work well with a write-back cache either.
So a lot of people bought these Pentium OverDrive CPUs, installed them, and then the complaints began. It mushroomed into a class action lawsuit presided over and encouraged by some Philadelphia lawyers. Well, the lawyers got rich and members of the class action lawsuit got $50 discount coupons to buy the Pentium OverDrive that did not work. The judge who approved this settlement must have been about as ignorant of computers as can be possible.
This was really Intel's fault. Motherboard manufacturers received Pentium Overdrive prototype chips with the more sensible write-through cache, so that's what drove the motherboard designs. Some bright bulb at Intel changed the design to use the marginally faster (we're talking <1%) write-back cache.
Fixing the write-back cache problem was simple. Intel made an "interposer", a thin circuit board inserted between the socket and the CPU. The job of the interposer was to force the CPU to boot up and run with a write-through cache. So they say. In my years of dealing with 486's, Pentium OverDrives and 486-workalikes from AMD and Cyrix, I never saw an actual interposer. I sold a few hundred kits with very fast AMD 486-like chips to disgruntled Gateway customers.
If the members of the lastest Apple class action lawsuit are lucky, the settlement may be a generous one like a discount coupon for last year's iPhones sitting in an Apple warehouse unsold.