I had 17 of these at one time the heatsinks can not handle 20 antminer s-3 chips. more of a size issue the chips won't fit.
I liked this gear. I used about 85 watts per unit with atx power. they did not overheat using 85 watts.
So they could do more like 10-12 chips since these s-3 chips can pull 7 or 8 watts on the top end. My sticks are doing freq 250 and pull around 5.5 watts
What I'd like to see would be a replacement for the Gridseed Gblades - the original "5.2 Mh/s Scrypt" per pair ones not the blacks.
I'm SURE, given the junk power regulation stuff on those, that there are a bunch around that have died or died on one "blade" but not the other.
HS on those should easily handle up to 20 chips, depending on the voltage they're run at.
Optimally voltage adjustable, but a 16-to-20 chip string should run pretty efficiently.
I figure (based actual power usage of my S5s) that the board (with a gold PS) would use about 40% more power at the wall than the chip specs, and I get the following:
16 string would be .75 volts - 286 GH/s at 155 watts (might be marginal these heatsinks but should be OK with a good 90mm fan)
18 string would be .666 volts - 200 GH/s at 80 watts (interpolating here, but this would be viable with the "specified" GBlade 12V/10A power supply per side)
20 string would be .6 volts - 165 GH/s at 58 watts (pretty close to a direct match on power consumption with the original GBlade, viable with a barrel power connector)
The 16 string would be kind of like a "quarter S5", a hair more efficient but not a bit diff.
The 18 string IMO would be the best tradeoff of performance vs. power usage and should run plenty cool on these HS with the original fan.
The 20 string would be a VERY nice high-efficiency replacement.
Board should be 4" x 8" to fit the original HS "pad", but could be longer on the 8" side for low-power components that don't really need the HS (like the UART and possibly a microcontroller). The pad would make it trivial to put the BM1384s on one side of it and make good heat transfer to the HS itself, put the other "taller" stuff on the other side (you have about 3/4 inch of space to work with if you design the boards to "interleave" or put tall components on a part of the board that sticks out past the HS).
If you could get any of these configurations built and sold for under $120 or so they'd be a winner!