Bootcamp performance issues

Your 13-in has an Intel GPU, unlike the 15-in models which can have dual GPUs. The AMD GPU in the newer Macs si fairly competent, but is still a mobile GPU, unlike a Desktop in iMac or iMac Pro. DPC does not show much variance, but has it in the 'yellow' zone during the test. If your performance is different on Battery vs. Power Adapter, check Power Options -> Advanced Settings and look at Processor Maximum and Minimum states.

The older i5 and newer i7 come with different GPUs, so performance may not be comparable for video. Do you still have the old Mac? If yes, run the DPC on it as well.

In some cases, the Intel HD4K on my 2012 Mac provides better performance compared to newer GPUs.

With the current settings, speed stepping of the CPU should work normally. In some cases, such stepping can cause video jitter. It can also reduce heat. You can test, and if it behaves the same way, you can fall back to the current settings.

You can also try the High Performance setting.

This is a standard Windows driver from Microsoft/Intel - Intel Corporation - Display - 2/28/2018 12:00:00 AM - 23.20.16.4973 - not the one provided by Apple. As a check, run BCA, and download the Apple package using Action -> Download and open Bootcamp.xml, and check for the Intel driver version in that list and post the version number.

From the file...

<Name>Intel(R) HD Graphics

<InfName>igdlh64.inf</InfName>

<Class>Display</Class>

<ClassGUID>{4D36E968-E325-11CE-BFC1-08002BE10318}</ClassGUID>

<CatalogFile>igdlh.cat</CatalogFile>

<Provider>Intel Corporation</Provider>

<DriverVer>04/21/2017,21.20.16.4664</DriverVer>

<ServiceBinary>igdkmd64.sys</ServiceBinary>

<HardwareID></HardwareID>

<isX64>yes</isX64>

</Name>

<Name>Intel(R) Display Audio"

<InfName>IntcDAud.inf</InfName>

<Class>MEDIA</Class>

<ClassGUID>{4d36e96c-e325-11ce-bfc1-08002be10318}</ClassGUID>

<CatalogFile>IntcDAud.cat</CatalogFile>

<Provider>Intel(R) Corporation</Provider>

<DriverVer>06/19/2012,6.14.00.3097</DriverVer>

<ServiceBinary>IntcDAud.sys</ServiceBinary>

<HardwareID></HardwareID>

<isX64>no</isX64>

</Name>

<Name>Intel(R) HD Graphics

<InfName>igdlh64.inf</InfName>

<Class>Display</Class>

<ClassGUID>{4D36E968-E325-11CE-BFC1-08002BE10318}</ClassGUID>

<CatalogFile>igdlh.cat</CatalogFile>

<Provider>Intel Corporation</Provider>

<DriverVer>10/31/2013,9.17.10.3347</DriverVer>

<ServiceBinary>igdkmd64.sys</ServiceBinary>

<HardwareID></HardwareID>

<isX64>yes</isX64>

</Name>

You will need to fall back to the Generic VGA drive, remove the current Driver and uninstall the adapter, remove the driver from DrvStore, and install the Apple driver. Also, disable the Windows Update for the specific PID/VID using gpedit.msc .

Also see How to stop Windows 7 automatically installing drivers .

What are the options under Battery Settings?