What you need to download for Rock Band 3 on RPCS3.

Before you begin, make sure your drivers and operating system are up to date.

Prerequisites

Let’s start by downloading 7-Zip, which will open the compressed .7z archives most of these downloads will be stored inside of. If you already have 7-Zip or an alternative installed, you can skip to the next steps.

[Click here to go to 7-Zip’s download page].

A screenshot of 7-zip.org's download page, with a cursor hovering over the 64 bit .exe installer.

Now, let’s go ahead and install Microsoft Visual C++ 2019 Redistributable, which is required by RPCS3. You probably already have this, but it doesn’t hurt to double check.

[Click here to download Microsoft Visual C++ 2019 Redistributable]

Once it finishes downloading, open it up and install it.

A screenshot of Microsoft Visual C++ 2019 Redistributable's installer prompting the user to accept the license terms and conditions and to install.

RPCS3

Next, let’s download RPCS3.

[Click here to go to RPCS3’s download site].

Scroll down a bit and download the Windows version.

A screenshot of RPCS3's download website, with a cursor hovering over the download button for the Windows version.

Once it downloads, extract the .7zip file.
A screenshot of the right click menu from Windows Explorer highlighting "Extract files..." from the 7-Zip category.

I would strongly suggest extracting the files into “C:\Games\RPCS3” or a separate internal drive to avoid permissions issues. Also, untick the box that will create a sub-directory, as shown highlighted in the picture.

Avoid installing to and running from an external drive or from a synced folder (Dropbox, OneDrive, etc.), as this usually leads to an unstable experience.

A screenshot of the Extract window from 7-zip. It shows the "Extract to" as C:\Games\RPCS3 and the box below it unchecked.

Firmware

Once that’s extracted, [download the PlayStation 3 system software from Sony’s website]. Scroll down until you get toUpdate using a computer.” Click that to expand, then click on “Download PS3 Update.

If you’re using a Chromium-based browser like Chrome or Edge, MAKE SURE YOU RIGHT-CLICK AND “Save link as,” or your download MAY become stuck.

A screenshot of Sony's "How to update PS3 console system software" page with the "Update using a computer" subcategory expanded.