In the AMD website, both HD 7770 and R7 360 driver download page is exactly the same (with the same file size as well).
So, I do not need to reinstall anything, right?
You absolutely should atleast reinstall it ( better yet, clean install) I think this would resolve some future performance issue like Techsource had when benchmarking the RX 470 as he used the same driver installation for all of his radeon cards, but found out that the RX 470 underperformed, but when he did a clean install, that fixed the issue.
It is a good idea to go through the clean driver procedure (uninstall drivers, run Display Driver Uninstaller in safe mode, install new drivers) when there is a hardware change, but it's not mandatory.
I think I'll test it. Maybe it is not necesary. The download driver page for both of those cards are exactly the same...
Let's see how it goes.
I'll report back when the testing is complete.
Ok, I'll do a clean install then.
Retrieving data ...