Unfortunately, you are not alone.
PC Sounds like a Jet Engine - Technical Support - Diablo IV Forums (blizzard.com)
GPU Load Increase While Talking with Vendor - Technical Support - Diablo IV Forums (blizzard.com)
GPU going mad in inventory / vendor menu - Technical Support - Diablo IV Forums (blizzard.com)
GPU Temp skyrocket when in inventory interface - Technical Support - Diablo IV Forums (blizzard.com)
The best thing we can do is be vocal and visible by keeping these threads at the top.