For one thing, chips have wider registers and can address more memory. In the 80s, you might have used an 8-bit CPU, but now you almost certainly have a 64-bit CPU in your machine. I’m not going to talk about this too much, since I assume you’re familiar with programming a 64-bit machine. In addition to providing more address space, 64-bit mode provides more registers and more consistent floating point results (via the avoidance of pseudo-randomly getting 80-bit precision for 32 and 64 bit operations via x867 floating point). Other things that you’re very likely to be using that were introduced to x86 since the early 80s include paging / virtual memory and floating point.