For my it wasnt worth to installing an 8087 FPU.. I left it just off.. Mostly programs did used the co-processor(there is only one game, that you already mentioned). But iam dont have a IBM 5150 here but it is just an turbo XT clone board iam using.
I think its should have more benefit on faster computers..like 286 and 386s.

bucket wrote:

I was sitting here fantasizing about getting my hands on my dad's old IBM 5150 and tricking it out. I made a mental list of the things I'd need to add to it: 8MHz CPU, 3.5" floppy, 8087 coprocessor... but what actually uses the coprocessor?

I did a short Google search and discovered that there were plenty of applications that took advantage of it. CAD, database, and drawing programs (and Windows!) are a few examples. But what about games? Supposedly SimCity uses it, and I saw somewhere a while back that a game called Vette! does as well. I began to wonder if the old SubLogic flight sim did as well. It seems like any old 3D game would benefit greatly.

Anyone have anything to add to the list?

Any game released back then wouldn't strictly require the co-pro, just have an option to use it if one is available. Adding a co-pro was an expensive proposition back then if you didn't really need it.Anyone who wrote games that strictly required the co-pro or else they wouldn't run would find themselves out of business because not enough people would be able to play their games to be profitable.

FPUs only became widely used in gaming with the Pentium, even when the 486 included an FPU is wasn't used that much in games.
If you want to use a 8087 in an XT you could write your software yourself. For example, Turbo Pascal version 3 included a special TURBO-87.COM executable which could generate code for the FPU. With Turbo Pascal 4 this became an option in the compiler. TP3 is freely downloadable today.