Dell Latitude E6540 performance issues and very slow boot

Purchased this Dell Latitude E6540 online without hard drive, battery and power supply and according to seller laptop suppose to be fully functional when all missing parts fitted.

After fitting all missing parts i installed Windows 10 on it, that didn't take too long since laptop is really high spec. After all initial setups were done i noticed some performance issues: when i booted laptop with power supply connected it took laptop to be fully functional more then 2 minutes witch is really poor since this Dell Latitude E6540 has 256GB SSD, 16GB RAM and Intel Core i7 processor.

Troubleshooting and testing:

Since i have never seen something like that before then i went trough full cycle: changed ram, changed hard drive, loaded bios default settings, used different power supply, booted laptop without battery with just charger connected and guess what.. no change.

What caused slow performance: 

Turns out it was using 90W power supply instead i should have been using 130W and that solved all issue. I only found that out when i booted laptop with just battery power and laptop started and was fully functional in less then 30 seconds witch is acceptable and good speed for such high spec laptop.

So here is very simple lesson: Do not use generic or lower wattage power supply on this laptop, if it requires 130W then get it dont be cheap:) and generic chargers are really no good for Dell laptops anyway. See video of the boot time below: 

Some basic specs below:

❖ Screen: (15.6") diagonal Full HD BrightView LED-backlit (1920 x 1080)
❖ Processor: Intel® Core™ i7-4800MQ Processor (6M Cache, up to 3.70 GHz)
❖ Ram: 16 GB DDR3 SDRAM (2 x 8 GB)
❖ Graphics: Intel HD Graphics 4600 + 2GB AMD Radeon HD 8790M
❖ Wireless Connectivity: 802.11b/g/n
❖ Optical Drive: DVD Super Multi DL
❖ Hard Drive: 256GB SSD
❖ Operating System: Windows 10 Pro 64-bit with MS Office 2013
❖ Sound: Stereo Audio
❖ 0 x Universal Serial Bus (USB) 2.0 / 4 x Universal Serial Bus (USB) 3.0
❖ Ports: HDMI / RJ45 LAN / Digital Media Card Reader
❖ Power: 130-watt AC adapter / Lithium-ion battery