Very slowly lightroom

Hi

I am using LR 6 more than 1 year. In the past 3 weeks I have speed issues, LR working very very slow (8-10 seconds from one photo to other) after 10 minutes of use, in the develop module, and even exporting of 1500 photos takes 12 (!!!!!!!) hours (it was 3-4 hours). I tried to re-install, installing the new Classic ver, GPU off/ on, purge cache (cache size 70 GB) ,creating new catalog, cleaning space on my SSD drive, update nVidia driver, overclocking to my CPU, build 1:1 previews and anything that may help. This is my sys info :

Lightroom version: 6.12 [ 1125239 ]
License: Perpetual
Operating system: Windows 10
Version: 10.0
Application architecture: x64
System architecture: x64
Logical processor count: 12
Processor speed: 3.4 GHz
Built-in memory: 16218.3 MB
Real memory available to Lightroom: 16218.3 MB
Real memory used by Lightroom: 1299.2 MB (8.0%)
Virtual memory used by Lightroom: 1480.1 MB
GDI objects count: 587
USER objects count: 2115
Process handles count: 1314
Memory cache size: 844.3MB / 3824.1MB (22.1%)
Maximum thread count used by Camera Raw: 7
Camera Raw SIMD optimization: SSE2,AVX,AVX2
Camera Raw virtual memory: 748MB / 8109MB (9%)
System DPI setting: 120 DPI
Desktop composition enabled: Yes
Displays: 1) 2560x1440
Input types: Multitouch: No, Integrated touch: No, Integrated pen: No, External touch: No, External pen: No, Keyboard: No

Graphics Processor Info:
GeForce GTX 1060 6GB/PCIe/SSE2

Check OpenGL support: Passed
Vendor: NVIDIA Corporation
Version: 3.3.0 NVIDIA 382.05
Renderer: GeForce GTX 1060 6GB/PCIe/SSE2
LanguageVersion: 3.30 NVIDIA via Cg compiler

Installed Plugins:
1) Loupedeck