It does AVX2 at half speed, AVX1 at full speed, but in return it runs at full clock rates with AVX, so it's not as bad as it sounds.
Most programming related workloads I can think of hardly benefit from avx2. Also, the additional power draw while using avx on intel is considerable, despite the clock rate drop; so perf/watt may not be as much behind as one might initially think.
This downside is likely to become slightly more serious as time goes on and more software uses avx2; but it's certainly not crippling.
What is SIMD support like for Ryzen? Does it do avx2 or something similar?
It's true that server components are generally loud. If you have the room, I recommend my setup - which is to have a (home build) rack in the basement, and run long DisplayPort cables (and USB extension cables) to the desk. Or build a closet around a rack in an office, which can be soundproofed. This does push it to the next level in terms of work involved, obviously (and cost as well if you don't have tools or time to DIY most of it).