Upgrade possible?

No G-series Mac can run higher than Mac OS 10.5.8,. and the non-Intel processor will give poor performance with modern web video technology. The processor is not upgradeable.

That G5 iMac (identical to mine) can play iTunes videos, but there are two updates you must perform: one is the version of Flash Player, the other is to have an alternative to Safari, namely TenFourFox.

Flash Player

You can check here: http://www.adobe.com/products/flash/about/ to see which version you should install for your Mac and OS. Note that version 10,1,102,64 is the last version available to PPC Mac users*. The latest version,10.3.183.23 or later, is for Intel Macs only running Tiger or Leopard, as Adobe no longer support the PPC platform. Version 11.4.402.265 or later is for Snow Leopard onwards.

* Unhelpfully, if you want the last version for PPC (G4 or G5) Macs, you need to go here: http://kb2.adobe.com/cps/142/tn_14266.html and scroll down to 'Archived Versions/Older Archives'. Flash Player 10.1.102.64 is the one you download. More information here: http://kb2.adobe.com/cps/838/cpsid_83808.html

You should first uninstall any previous version of Flash Player, using the uninstaller from here (make sure you use the correct one!):

http://kb2.adobe.com/cps/909/cpsid_90906.html

and also that you follow the instructions closely, such as closing ALL applications (including Safari) first before installing. You must also carry out a permission repair after installing anything from Adobe.

(If you are running a PPC Mac with Flash Player 10.1.102.64 and are having problems with watching videos on FaceBook or other sites, try the following solution which fools the site into thinking that you are running the version 11.5.502.55:)

Download this http://scriptogr.am/nordkril/post/adobe-flash-11.5-for-powerpc to your desktop, unzip it, and replace the current Flash Player plug-in which is in your main/Library/Internet Plug-Ins folder, (not the user Library). Save the old one just in case this one doesn't work.

TenFourFox

I was in the same boat. I run a G5 PPC iMac and I could not watch flash videos as it struggled on YouTube.

For reasons that passeth all understanding, they nearly all work with the PPC version of Firefox, called TenFourFoxG5.app, once you have enabled plug-ins, as it does not natively support Flash.

You can download TenFourFoxG5 from here:

http://www.floodgap.com/software/tenfourfox/

Now for the interesting bit: TenFourFox, like Firefox, does not support most plug-ins. Unless you are prone to headaches (in which case don't) you can read about that here:

http://code.google.com/p/tenfourfox/wiki/PluginsNoLongerSupported

But there is a workaround!

Open TenFourFox and type in the address bar: about:config (no spaces) and click return. This gives you a warning that it might harm the application. Ignore that and click on 'I'll be careful, I promise' and you get the config file that you can edit - with great care.

Look/search (scroll down) for: tenfourfox.plugins.enabled

Set it to true. (Double click it to toggle it)

Now close TenFourFox, open it again, and Flash will now work, as it now uses the plug-ins that Safari has stored.

I am using Flash 11.5.502.55 in TenFourFox and it works just fine.

You're welcome!

Happy Easter! 🙂

I really doubt that a PPC Mac can play Minecraft - but check with them.

Some discussion of MC and older Macs here:

http://www.minecraftforum.net/topic/741305-mac-system-requirements/