Go represents strings as UTF8 encoded bytes, while Java and .NET use UTF16 in memory.
This means that by default for "western" languages, Go is likely using less memory.
But the raw speed depends on compilers and benchmarks... and .NET/C# is improving quickly...
Comparing AWS Lambda Runtime Performance across Go, .Net Core 2.0
Go vs .NET Core in terms of HTTP performance – Hacker Noon
Performance is a Key .NET Core Feature
.Net Core 2 and Golang – John Adams – Medium
Performance Improvements in .NET Core 2.1 | .NET Blog
"The fastest backend web framework for Go."
Announcing .NET Core 2.1 | .NET Blog
.Net core or node js? [We increased throughput by 2,000%] · Raygun Blog