IE 8 RC 1 is Now Available for Download
I downloaded and installed IE 8 RC 1 on my machine. It works really well, the performance improvement is significant.
I would encourage you to give it a try, https://www.microsoft.com/windows/internet-explorer/beta/worldwide-sites.aspx.
Disclaimer, this is an Release Candidate, not RTM. There could be some issues, but overall, this is really good.