Selenium.WebDriver.ChromeDriver slow to launch - why?

I've created the simplest-possible NUnit test to initialise a ChromeDriver, and it's taking nearly 6 seconds to run. Most of the time (roughly 4s) is spent with a blank, inactive Chrome window.

The ChromeDriver.exe window appears almost instantly.

My unit test looks like this:

[Test]
public void Simplest_Possible_Test()
{
    var options = new ChromeOptions { Proxy = null };
    using (new ChromeDriver(options))
    {
        // Do nothing
    }
}

and I'm using these nuget packages:

<package id="NUnit" version="3.12.0" targetFramework="net47" />
  <package id="Selenium.Support" version="3.141.0" targetFramework="net47" />
  <package id="Selenium.WebDriver" version="3.141.0" targetFramework="net47" />
  <package id="Selenium.WebDriver.ChromeDriver" version="78.0.3904.7000" targetFramework="net47" />

My question is:

Is this slowness expected? Can I do anything to speed it up?