How to reproduce:
1. Open any HDRP project or create a new HDRP project
2. Switch Graphics API to Vulkan
3. Open Task Manager and inspect memory usage of Unity

Expected results: Editor memory usage remains similar to the memory usage when other Graphics APIs are used like DX11 or DX12
Actual results: Editor memory usage is higher by up to 2-3GB when using Vulkan compared to other Graphics APIs

Reproducible with: HDRP 7.5.2, 7.5.3 (2019.4.20f1), 10.2.2, 10.3.1 (2020.2.4f1), 11.0.0 (2021.1.0b7), 12.0.0 (2021.2.0a4)

Notes:
1. After entering Play mode the memory usage can jump up to 2GB additionally and stays that way after exiting Play mode (doesn't grow more when trying to repeat this)
2. Rarely, when closing the Editor it can hang and grow memory usage up to 8GB
3. Memory overhead is lower with the new HDRP template(from 2020.2) so it might suggest that assets are a part of this issue
4. Doesn't reproduce with URP (Memory usage with Vulkan compared to DX11 is only about 200MB higher)