Well unfortunatlly as fas as the am4 platform and m-atx is concerned,
there isnt really that much decent to choose from wenn it comes to motherboards.
Because vrm wise they pretty much all suck.
If you want a decent vrm on a am4 board then you are basically stuck to ATX.
And then in particular X370 / X470 higherend boards.
X470 boards with a decent vrm implementations in order.
Highend:
-
Asus crosshair VII Hero: pretty much the best board vrm wise.
And also a really great bios. -
Asrock X470 Taichi: Also a pretty decent vrm, offers a really good value for money in terms of connectivity features.
The Bios still could use some improvements on certain items.
But its not a bad bios to work with overall. -
Asrock X470 Taichi Ultimate: Decent board aswell, basically the same board as the normal Taichi, but this particular board comes with an additional 10gbe nic.
But its kinda questionable that additional nic being worth its additional more pricing over the non Ultimate. -
Gigabyte Aorus X470 Gaming 7. Pretty decent board aswell.
Great vrm and a proper heatsing design to cool the powerstages.
Its just that the bios could be a littlebit wonky sometimes.
But that will be improved every bios update most likelly.
Midrange:
-
Asus X470-F Strix, pretty decent board with a decent vrm implementation aswell.
The nice thing about this board is that it comes with certain rog features.
The downside of this particular board is that its lacking a couple of features like pnboard powerbuttons and postcode readouts.
Also a B-clock generator is missing, and only 5K caps.
But overall its a pretty decent board, and if you install it in a case,
then most of those cons shouldnt really be an issue. -
Asus X470 prime Pro: Decent board again with all the base features that most people would need.
Also good vrm aswell.
Those are pretty much the better X470 boards to go with.
But if you still prefer m-atx, then maybe Threadripper might be interesting for you.
Asrock offers a X399M (micro atx) Taichi motherboard for Threadripper.
And its a really great board wenn it comes to its vrm implementation, a straight 8 Phase for Vcore +3 Phase for Soc digital IR vrm implementations controlled by 2x IR35201 pwm´s.
And with 60A IR3555 powerstages all the highest end stuff.
Also the 1900X currentlly is arround the same price as the 1800X.
So that isnt really going to cost you much more.
But with X399 you do get allot more expendabillity, and more upgrade room to a higher core count sku if needed in the future.
The only downside is that the 1900X uses more power and is a littlebit slower wenn it comes to gaming compaired to a 2700X, so if gaming is priority nr1 then Ryzen 2700X is probablly going to be a better choice.
But newer TR sku´s might be released soon.