I've tested these in both a Beige G3 tower, a B&W G3 400, and a Celeron 1GHz. All recognized them fine and booted without issue. I ran memtest86 on them over night and had no issues (I was also testing replacement capacitors on the mobo at the same time). I was surprised the Beige saw them with the whole 256MB. Max your Beige with all 3 of these for a total of 768MB RAM. These worked in the B&W so I'd assume them to work in a Yikes! as well, and probably any other PC100 capable system. Being ECC they'd also be great to put in a PC100 server that needs it. They are NOT registered, as there are no extra chips other than the RAM and the SPD chip.
Labeled as:
256MB ECC T8
PC100-222-620
P30959 TDL256-0716
The 18 RAM Chips are:
Infineon
HYB39S128800CT-7.5
C2
On a Cubig SM256 PCB
$25 each, plus shipping from 64053.
PM me if you are interested. I do have a PC100-based server I can test them in if someone needs it, but it's very noisy so I don't like leaving it on all night/day for a good test.
CLARIFICATION:
I tested them in the Celeron system over night, and it had suffered the capacitor failure that was endemic during the P3 era which I fixed and was testing simultaneously.