So it's about time I updated this thread.
I've been buying a lot of parts over the last few weeks all to allow me to flash a GPU to run in my G4, first of all was my GPU flashing rig, may I present the trusty Dell Dimension 4600 purchased for £7, I chose this as it had an AGP port as well as a floppy drive.
I later found the floppy drive was dead. I had no luck flashing from CD-ROM (NVFlash kept crashing) so I had a look online and found someone throwing out some old computer bits including a couple of towers with floppy drives. Went and picked them up (free), they had been sat under a lean to shelter by the side of a house and thus smelt a bit 'swampy'. I decided not to power them up but removed all the parts apart from the power supplies and took the cases to the dump. Got some other bits from them that will be going in the G4 but I'll talk about them another time. Anyway the floppy drives from these worked perfectly so I put one in the Dell Dimension and got going with the flashing.
Anyway I hadn't even mentioned what I was flashing, I got a PNY Geforce 6200 AGP 256mb off ebay for £5, I had somehow decided in my head it looks similar enough to the XFX one so I could clearly use the XFX Mac rom I downloaded. Picture below mid flashing, the Dell wasn't connected up to my network so I was using my Thinkpad to download everything.
Taped up pins 3&11 on the 6200 and put it in to my G4, moment of tru....uh oh.....that didnt go quite as planned, my PNY card clearly didnt like the XFX bios, I kept the original bios so I'll have to flash it back to stock at some point.
At this point I wasnt too sure what to do, my living room looked like a bomb full of early 2000s graphics cards had gone off, I had the cards below left over from the Dell and the other PCs I got:
Radeon 9250 256mb (couldnt find a mac bios)
Radeon 9650 (G5) (Dell wont display any video with it, probably as its a mac card)
Geforce 4 MX 420 (from the Dell)
Radeon 7000 PCI
I went with the Radeon 7000 as at this point I just wanted something that would output DVI to run my Formac 2010 (Rage 128s DVI doesnt work). Flashed the bios with atiflash, worked first time!!
So now was the moment of truth, does the DVI work?
YES!!!!!!!!!!!
Decided to upgrade the annoyingly loud stock fan with a Scythe Gentle Typhoon AP-15 I had lying around. Soldered on the original Mac connector.
I'll keep the stock fan for if I ever need to go back to it.
Celebratory run of GeekBench, not sure if this score is actually any good;
So thats where I'm up to for now, changing a graphics card has never been so stressful and I now have tons of excess hardware. The radeon 7000 isn't going to remain as the main GPU as it isn't much faster than the Rage 128 but it'll do for now and I'll probably leave it in as a secondary GPU. Not sure what to go with from here, I'd like something with a bit of power that is known to work in the digital audio.