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Potential Wallstreet II VRAM Upgrade

I picked up a Wallstreet II 233 MHz/512kB cache/4MB VRAM off the Low End Mac Swap List recently. I got it on the cheap because it had begun to fail to boot for the original owner. This is a common problem among older Wallstreets. And if you know your way around a soldering iron, sometimes it's fixable. In this case, the power connector had a loose connection with the sound card, and a little resoldering solved the problem. But while I was in the guts of the book, I noticed something that I'd never really paid attention to before. An empty solder pad... And in true AppleFritter fashion, I had to explore some more!

Supposedly, the Wallstreet II has a maximum VRAM limit of 4MB, but to the best of my knowledge, that is only because there is no way to install more VRAM. It is well known that some lower-end Wallstreet I models only had 2MB of VRAM with empty solder pads on the underside for the extra 2 1MB VRAM chips. That's not what I'm seeing on the Wallstreet II. For more, keep reading...

If you have any information about this subject, please don't hesitate to let me know!

The Crime Scene
Underneath the modem and beside the CardBus card cage, there is an empty solder pad at position J14. The pads look to me like what might be an intended location for a card-edge connector of some sort. In fact, there are clearly 144 pins and a blank area for some sort of "key."

The empty solder pad is squarely in the middle of the picture. The top right is the CPU daughter card with 64MB RAM and G3/heat transfer disk. At the bottom is the modem on top of the overturned keyboard. At the top left is the CardBus card cage and controller. Immediately beneath the empty pad are 2MB of VRAM. To their right is the modem connector.

The Evidence
The slot looked familiar to me. I tried to think of what kinds of cards use 144-pin keyed connectors, and only two good suspects came to mind. The first thought was that a SO-DIMM RAM slot was intended for this space. But the CPU daughter card already has two RAM slots... And sticking a RAM slot way out here didn't make a lot of sense to me. On the other hand, the connector is very close to 2MB of the 4MB total of VRAM and virtually on top of the ATI Rage LT GPU (on the underside of the board, but nearby). And then I recalled that my beige G3 has an SGRAM connector very close to it's ATI Rage II+DVD chip...

I'm embarrased by how dirty the inside of my beige G3 is. Please, don't talk about it. :-(  But here you can see the 144-pin SGRAM connector on the beige G3 motherboard. Note the 2MB of VRAM on the motherboard. As an aside, does anyone know what the heck the "DVD" means in "Rage II+DVD?" AFAIK, these things can't decode DVD without the help of a hardware MPEG-2 DVD decoder on the personality card.

The Opening Statement
After looking at the beige G3's SGRAM slot, I pulled the 4MB upgrade I had installed in order to compare it to the empty solder pad on the Wallstreet. I also compared the pad to a standard SO-DIMM RAM card.

This picture shows the RAM card compared to the empty pad. As you can clearly see, the notch on the RAM card does not quite line up with the blank spot on the solder pad.
This pictures shows the 4MB SGRAM from the beige G3 contrasted against the solder pad. The notch lines up perfectly! So that's it - this must be an empty SGRAM connector solder pad. Could soldering a connector in and putting in 4MB of SGRAM double the amount of VRAM available ont he Wallstreet II?

The Closing Statment
Still to come. I'll fill this in with my progress towards installing an SGRAM connector if I decide to try it.

The Judgement
Still to come. If I undertake the project to install an SGRAM connector, I'll post an update here about the results.


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