These sound like they would be HP z220/230 or similar brand line of SFF terminal/workstation.
I see the k620 uses a GM107 core, like FourOh said it's used elsewhere. It's actually a chopped down GTX 750, the same as a GTX 745 (i think OEM card) the following is liberated from
wikipedia
There are essentially three different GM107 cores the biggest with 640 cores, the next has 512 and the last has 384. The gtx 750ti comes with the 640 cores as well as the Quadro k2200, the Quadro k1200 and the gtx 750 have 512 cores and the gtx 745 and quadro k620 have 384 cores. Also worth noting is its ddr3 ram on the smaller cores. It is double precision capable but I think it's performance will be pitiful as I think the single to double precision ratio on all maxwells is 1/16
My 750ti's can do about 128k-192k each a day on GPU grid running the LONG WUs that take about 18-19 hours each. I haven't dabbled with them much or enough to compare results project to project but some projects absolutely suck on them, pretty sure milkway was pathetic. MooWrapper is about 4x slower than a 270x in credit output.
Yeah I've been beating on them but here's the catch, they're near silent. Very low heat, highest core temp i saw on one is 63c, usually see around mid 50s. Low power, usually require no PCIE power cable. Also I can watch Netflix, browse web, watch movies (VLC) while its crunching without any choppiness or hesitation, maybe certain projects but I can't recall. They're good cards.