I have a multi distro laptop (Ubuntu MATE / Mint Cinnamon / Debian) (32-bit Inspiron 6400 2Gb ram 320GB WD HDD) that ignores the alleged limit of 4 primary partitions. I have 15 and counting.
I'm new to modern Linux and am having a play. I last had a play back in the 90s with GNU Slackware I also have an old Acer 64-bit desktop which will only allow 4 primary partitions. I might try loading another 2 distros on to see if the 5th one boosts. Any ideas why this one machine allows over 4 primary partitions and the other does not?