Like Unknown_K said, the g3 - for a video card to go into a 6100, you need an adaptor to turn the PDS port sideways. These adaptors are usually little more than an inch and a half high circuit board with tracks taking the PDS slot to another PDS connector at right angles to the original.
The one pictured is a G3 CPU upgrade, which also works as a right angle adaptor, with a graphics card plugged into it - and it's advertised as *just* the graphics card. Arguably, the G3 that the seller neglected to notice is worth more than the video card itself.
What Dana and Unknown_K said. The purple heatsink is the sign of a Sonnet G3 upgrade. Something all soldiers should keep in mind out in the field [] ]'>
I have a G3 upgrade in one of my 7100/66 systems, the slowness of the rest of the system slows it down quite a bit. A G4 in a Nubus PPC is about worthless in my opinion.
I got a g3 card in my pm 7600, it's faster then my g4 at 400mh, as the card is 460mh or somthing around there, I plan to try installing 10.2 on the computer, but that hdd is so small, so yea,
Unfortunately you won't be able to get any version of Mac OS X onto your PM7100, nor any other NuBus Power Mac, even with a G3 upgrade. Mac OS X has absolutely no support for NuBus architectures whatsoever, meaning that you're stuck with either System 7 - OS 9, or a PowerPC linux distro that is compatible with NuBus (such as MkLinux)