Cheers to Blender and the rewritten 2.8 version. Some of u may have felt like something was going on lately while enjoying everything in the new release. Well. Every software company in the industry is cutting prices now. This Blender release is pretty spectacular.
I’m not celebrating,just YET–blenders new design is much better I think tho not all on board, such as life- but ya as yet, blender’s viewport isn’t entirely prime time ready for my 2.3 MIL mesh, only app I’ve tested so far that is,is 3dsmax,that ofc I can’t afford! 
But ya for smaller things for now its wonderful and yes, a great equalizer.
U must have something going on with your settings. Ive had millions of poly rendered in blender, and it performs just fine. Ive never had any issues with tris count except my hardware limitations.
Im not ‘rendering’,I’m actively working in the viewport everyone knows has work to be done on it, and it may or may not come in 2.81:) I was also 100% correct in saying 3ds max 2020 ,yes a LOT of money most not available to many consumers ,runs circles around blender 2.8 current, on my hardware,the same one I use with blender 2.8 current.
I mentioned this , not because you aren’t having this issue, but others may indeed lilke myself, see this issue themselves
You say I must have some setting off,but offer no guidance in re-configuring said setting.I have tons o f time as my presence here illustrates and would love to find said setting and rectify the horrific slowdowns I face in blender 2.8 current . I believe in OSS ,and in other less free software where there is incredible merit not quite as well served elsewhere.I’v asked time and time again on blenderartist forum,a great community for help with blender, and no setting offering has yet been made and my mesh is too large to use subdivision modifier on,the word there accuately faick atm,is wait for ‘viewport’ performance modificatons somewhere as I recall,around 2.81 ISH.
Thx