From the London VPS:
- Two brokers with servers in the LD4 data centre: 1 to 2 ms.
- One broker in New York: about 70 ms.
- One broker that didn't publish a location: around 12 ms, which suggests somewhere in western Europe, maybe Amsterdam or Frankfurt.
Does it matter for scalping? For my style, with 5 to 10 pip targets on M1 and M5, the difference between 2 ms and 15 ms makes no measurable difference in fills. The difference between 15 ms with jitter and 2 ms stable showed up in my slippage logs only around the open and data releases.
The bigger point is knowing where your broker is. If you're in Asia trading a broker in London, a VPS close to the server can matter more than which broker you choose.
How do others measure this? I used the platform's own ping display plus a simple tcp check.