Windows 8 not showing 5GHz networks

I had the same problem connecting to the 5Ghz band with a Linksys WMP600N PCI card to a Linksys E4200 running DD-WRT build 19342 under Windows 8 Professional (RTM). The problem is definitely the driver that is included in Windows 8 as the same hardware had no problems under Windows 7. I was able to solve it by manually installing the Windows 7 (!) driver from the Linksys (Cisco) support website: Windows 7 Driver 04/30/2012 Ver.3.2.7 To do this:

1. Unpack the downloaded driver to your computer
2. In desktop mode, right click the wifi icon in the right lower corner and select "Open network and sharing center"
3. Click "Change adapter settings"
4. Right click you wifi adapter and select "Properties"
5. Click "Configure"
6. Go to the "driver"-tab
7. Click "Update driver"
8. Click "Browse my computer for driver software"
9. Click "Let me pick from a list of device drivers on my computer"
10. Click "Have disk"
11. Browse to the location where you unpacked the downloaded Linksys driver
12. Select your network adapter and click "Next" to install the driver
13. Close all windows Check if you see your 5Ghz band

Taken from Technet Answers