Not exactly. The Quadra 630 could take 196 megs (one 128 meg SIMM, one 64 meg SIMM, plus four on the board), and if you're running NetBSD or can write your own ROMs, you can get 260 megabytes in a Quadra 610 or 520 megabytes in a Quadra 650 / 800.
128MB is a hard ceiling for all of the 030 Macs right up through the IIfx. Apple hobbled every Quadra to 136MB with with a useless bank of 8M on the system board excepting the 900 and 950, which had the full four acres of 32pin SIMMs on their boards.
Cost and availability of 16MB 30 pin SIMMs would be what got me onto the 72-pin adaptation several years ago. I'd imagine, newer, higher density RAM ICs for 128MB might be surface mounted above and below the two acres of thruhole 30-pin SIMM sockets? Dunno, @trag is our memory boffin, he could figure out if we may as well shoot right past the 72-pin SIMM upgrade option?
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I guess it all depends on what people really want, as in terms of spending money on it? Purists may want the proprietary chips harvested from their dead board to populate a new design logic board that looks the same as the old in a sexy new color that you can't see anyway? I'd rather see some new possibilities opened up while we're at it. I'm not talking about featuritus as in add-ons, just about taking a more modular approach in the board design process. Think in terms of a layout blocked out for relatively easy rearrangement and adaptation to something like an SE/30 replacement board for the plastics of a dead Mac Portable, that's my notion, not Eleanor, but close.
The necessary parts and technology are in hand for a fully reversible, non-destructive SE30 Portable mod with a minimum of 640x400 on a perfectly fitting IPS panel.
One add-on though, a new format PDS card in this case, so to speak. Given @maceffects amazing developments based upon the Xceed 306-48, I don't see much difficulty in running the SE30 Portable's replacement panel at its native 1280x800 at a minimum of 16bit. A standard 306-48 build, its resolution trimmed down from 640x480 to 400 lines in 8bit color should work amazingly well as I currently plan. It's far better than 512x324 even in grayscale. Purists from either camp could knock it back to single bit and maybe even be turn down the backlight?
Maybe drop a RaspBerry Pi 6+ or better into the HDD Bay one day along with the SCSI2SD and browse the web at 1280x800@24bit at the press of a macro.
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If you weren't aware, there's a company that manufactures brand new replacement feet for the Quadra/Centris 610/PMac6x00 line and they sell them on eBay. A set of 4 are like $25 or something.
Alternatively, Performa 611x Macs often sell for very little on eBay for some strange reason. I picked one up recently with a CD-ROM, 16MB of RAM, a working 500MB hard drive, and case in excellent condition, for $20 plus $15 shipping.