Yes, there is a difference depending on how you configure proxy selection.
In Veeam, the number of simultaneous tasks a proxy can handle is based on the number of CPU cores of the server where the proxy is deployed. Typically, the default setting is one task per CPU core.
Each disk from a VM or volume from an agent is considered one task. So, if a VM has multiple disks, each disk may consume one task simultaneously. This is important when considering proxy load.
If you select proxies per job, all jobs will try to use the same proxies even if they are already busy, which may cause bottlenecks. If you configure proxies by repository affinity, Veeam can better balance the load across proxies during operations, optimizing task usage and performance.
In larger environments, using repository proxy affinity is generally recommended for better scalability and automatic load balancing.