HP Probook 650 G4 i5-8350u has halved CPU performance and max CPU power usage of only 11W-12W

[Hurrying]

Hi all,

I got a used HP ProBook 650 G4 with an i5-8350u (max. 3.6ghz), put in my own new nvme ssd (Kingston) and paired ddr4 2400 2*4gb also Kingston. I ran the memory tests from BIOS and they are good.

I got the laptop without the battery and I am using it with an HP adapter from my newer HP laptop (2.31A, 45W, 19.5V, specs on ProBook 650 G4 laptop say it is exactly appropriate).

The issue is it runs very slowly (225 points in Cinebench R15 instead of 650).

Upon installing Throttlestop I saw the CPU keeps at or below 1.6GHz while performing benchmark. Having set an undervolt of -0.125mV on the CPU, and turned on all the additional options, the performance now goes up, but now enough (477 points in Cinebench instead of 650).

The power consumption shown in Throttlestop only goes up to 11.5W - 12.2W under full load.

So my question is, is this due to the battery not being present, or some other cause?

How can I look at the BIOS event log, I read that it has records of all power issues but can not find it.

Can I try making a BIOS update first before the battery? (I know the BIOS update overwrites the event log, so I would first need instructions on viewing that one)

Can I return the performance of the laptop to normal, or at least diagnose exactly what the problem is before buying the battery?

On further testing to see if connector is faulty, and pulling DC jack several times in and out to try to adjust it in a better position in 10s, the tests were limited to 5W now, had to restart, enter BIOS, for performance to return ro 11W, so it seems the integrated controller is deciding to limit power usage. Can the information on this one be diagnosed with some software?