0.8.8 is the fastest build for Windows. In fact, until I could afford a newer machine (I had a modest Cyrix MII [Pentium 2 clone] with 256MB RAM and 16mb video card running at 500MHZ), I used 0.8.8 for years, and it ran demos and games with no frame skip at full speed.
The later versions are built for compatibiliity, but unless you run very specific (read: buggy) software, you'll find that most of the features you need are supported by 0.8.8.