As addressed in the comments on SO[1], x32 mode is actually still long mode.  It&#x27;s just a change in ABI to use the upper and lower 2GB of address space so that you can fit pointers in 32bits.  It doesn&#x27;t really act like a 32bit system because it isn&#x27;t it&#x27;s a 64bit system with a restricted address space.<p>That said it can be useful for certain loads where you aren&#x27;t consuming large amounts of memory but are doing lots of calculations.<p>[1] <a href="http:&#x2F;&#x2F;stackoverflow.com&#x2F;questions&#x2F;16841382&#x2F;what-is-the-performance-impact-of-using-int64-t-instead-of-int32-t-on-32-bit-sys#comment24292419_16841814" rel="nofollow">http:&#x2F;&#x2F;stackoverflow.com&#x2F;questions&#x2F;16841382&#x2F;what-is-the-perf...</a>