Update README

README.md

@@ -19,10 +19,10 @@ on a simulated 8-core 16-threads machine.
 | Firefox 89 libxul (1.64 GiB)  | 32.95s   | 6.80s    | 1.42s
 
 mold is so fast that it is only 2x _slower_ than `cp` on the same
-machine.
+machine. Feel free to [file a bug](https://github.com/rui314/mold/issues)
+if you find mold is not faster than other linkers.
 
-Feel free to [file a bug](https://github.com/rui314/mold/issues) if
-you find mold is not faster than other linkers.
+mold currently supports x86-64, i386 and ARM64.
 
 ## Why does the speed of linking matter?
 
@@ -189,7 +189,8 @@ If `mold` is in `.comment`, the file is created by mold.
 
 One reason is because it simply uses faster algorithms and efficient
 data structures than other linkers do. The other reason is that the
-new linker is highly parallelized.
+new linker is highly parallelized (i.e. optimized for _modern_
+multicore processors).
 
 Here is a side-by-side comparison of per-core CPU usage of lld (left)
 and mold (right). They are linking the same program, Chromium