Good question. Too bad we don't have an answer.
Last week's debut of Windows 7 RC on MSDN and TechNet, however, may be a clue. And it's not comforting. Microsoft had all kinds of trouble serving up Windows 7 RC to MSDN and TechNet subscribers last Thursday, with the download sites for both services eventually going dark. After several hours, Microsoft got the snafu untangled and put both sites' download sections back online.
What do I need to install the release candidate?
Microsoft has set the minimum requirements for the RC as a 1-GHz or faster processor; 1GB of memory; 16GB of free hard drive space for 32-bit, 20GB for 64-bit; and graphics that supports DirectX 9 with a Windows Display Driver Model (WDDM) 1.0 or higher driver.
WDDM, which debuted in Vista, was a marked change from the driver standard for the older Windows XP. The new driver model may be best known for the part it played in the still-alive "Vista Capable" lawsuit, in which consumers have accused Microsoft of duping them into purchasing XP machines that the company knew would not be able to run WDDM drivers.
If you're planning on also trying out the new "XP Mode" virtualization add-on, which will be released May 5 in beta, you'll need 2GB of system memory and an additional 15GB of disk space.
You'll also need a recordable DVD drive to burn the file you download, which comes as a disk image, or .iso file, to a DVD, which you'll then use as the installation disc.
If you're installing Windows 7 RC to a virtual machine, using, say, VMware's Fusion on a Mac, you can skip the DVD burning step and install directly from the .iso file. VMware posted step-by-step instructions in January for the beta; they're valid for the RC, too.
How big is the download?
The 32-bit version weighs in at 2.47GB, while the 64-bit tips the scales at 3.2GB. Both numbers are slightly higher than the corresponding beta. The XP Mode add-on is another 450MB or so.
Do I need a product activation key? How about if I already have one from the beta.
Yes, and according to Microsoft, yes again.
Microsoft will make keys for the RC available through the same mechanism it used for the beta, in other words, before you start the download, you'll be asked to sign in using a Microsoft Live ID and given a key.
But while Microsoft said that keys obtained for the beta won't work with the RC, others have countered that, in their experience, they do. Noted Windows blogger Ed Bott, for instance, has said that product keys obtained for the earlier beta "work just fine" with the RC.
Can I upgrade from the Windows 7 beta?
You can, although Microsoft doesn't want you to. As is, the RC blocks installation when it recognizes that the PC is running Windows 7 beta. Microsoft did this, it said back in early April, because it wants users to "experience real-world setup and provide us real-world telemetry."
Instead, Microsoft told users to either do a clean install -- wiping out their copy of Windows 7 beta, all the applications they'd added and all the files those applications had generated -- or revert back to Vista Service Pack 1 (SP1), which they had presumably been running before they upgraded to the beta, then install RC.
To get around the block, copy the contents of the Windows 7 RC DVD to a local folder -- a bootable USB drive works, as does any root-level folder on the machine running the beta -- then on that drive or in that folder, open the "Sources" folder. Open the "cversion.ini" file with Notepad, and change the value of "MinClient" to "7000." Save the file and run Setup.
Microsoft walks you through the steps here.