So here's an update, got the new heatsinks in, haven't had a chance to game on them yet, will be doing that shortly, but they seem to be pretty good stuff. They're light, but the base is fairly thin, so that makes sense. I scratched one with a screw driver just to make sure they're real aluminum - pretty sure they are:
Before picture:
Surprising those did as much good as they did - a 4-6C drop on 2 of the 3 iCX Memory temperatures, and drops across the board on the other temps, ranging from 0.5C to around 3C lower.
Now, witness the awesome powa of 20 of the 20x20x10mm goodnesses:
The top & bottom-most rows are lined up with the areas the VRMs of the card are in - I'm unsure of whether or not there are thermal pads there because I haven't seen a picture of someone taking their card apart/taking the backplate off & actually finding pads there... I may end up taking mine off after I order some thermal pads, and if they're not there, I'll put some there, cuz why not...
Arranged them for pretty uniform airflow, I think... wishing I'd gotten one more pack so I didn't have to put some of the silver ones back on, but ah well!
120mm fan just sitting on them, blowing at around 1000RPM - I figure that's plenty - might change it to an EK Vardar later when I get some more just cuz though.
I'll report back with temp comparisons to no-heatsinks vs the original heatsink setup in pic 1, vs the new heatsink setup.
These also came with thermal tape preapplied:
https://smile.amazon.com/gp/product/B07BDKN3XV/ref=ppx_yo_dt_b_asin_image_o04_s00?ie=UTF8&psc=1 link for anyone interested in purchasing some, they're $12 for 10 of them.