I have the following problem. I work with 2 systems, an Intel i7 4770K and AMD threadripper 1950x. If i render my benchmark scene ( 30 gb ram) The intel workstation runs smooth and starts rendering after 3 minutes. The AMD threadripper needs 2 hours to load the scene.
When the threadripper starts rendering, it does everything quick and fast, but the scene buffering/ loading all assets, takes a long time.
I work with the latest 2.79 blender release, no test build. Both systems have a clean windows 10 build and include all chipset drivers.
If i run the Blender official benchmark demo scenes, everything runs fine. Also the 16 gb production benchmark scene runs smooth. There is a difference between the intel and AMD system when loading, but it doesn't take more than 10 minutes extra for AMD and that's oke.
One more detail, the first 16 GB ram on the AMD system loads quick, but when it starts loading more ram than 16GB it slows down completely. I did a ram test in win 10 and everything was oke.
full specs AMD:
HTTA03 AMD Ryzen TR 1950X WOF 3400 TR4 BOX | GTEG30 GiBy X399 AORUS Gaming 7 X399 | HXLM63 CooMas MasterLiquid Pro 240 | TN7V2L03 be quiet! Pure Power 10 700W ATX24 | GTX 970
If more details are needed, let me know