AWS z1d.large CPU speed

Hello,

I understand you are looking for a faster EC2 instance type with just one Core. AWS provides a wide selection of instance types optimized to fit different use cases. 
 
This list of Instance Types might be helpful to you in selecting an instance that fits your needs as it breaks it down by CPU cores and threads per CPU core per instance type.
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/cpu-options-supported-instances-values.html
 
This link may be helpful along side the above link to learn more about each instance type:
https://aws.amazon.com/ec2/instance-types/
 
Possibly an Compute Optimized or Accelerated computing instance type would help speed up your application. Compute Optimized instances are ideal for compute bound applications that benefit from high performance processors. Instances belonging to this family are well suited for batch processing workloads, media transcoding, high performance web servers, high performance computing (HPC), scientific modeling, dedicated gaming servers and ad server engines, machine learning inference and other compute intensive applications. Accelerated computing instances use hardware accelerators, or co-processors, to perform functions, such as floating point number calculations, graphics processing, or data pattern matching, more efficiently than is possible in software running on CPUs. There are options for 1 core in both of these categories. 
 
I hope this is helpful in selecting an EC2 Instance that fits your needs. Best of luck