Use this small script to come across the fastest Cygwin Setup mirror for your location.

fastest_cygwin_mirror.ps1

function purge-any-pending-job {Get-Job | Remove-Job}

$measure_mirror_latency = {
    Param([string] $argument)
    $mirror_url = ($argument -split ";")[0]
    $sum_url = "$($mirror_url)x86_64/sha512.sum"
    $req = [System.Net.WebRequest]::Create($sum_url)
    $req.Timeout = 2000
    try {
        $dur = (Measure-Command {
            $res = $req.getResponse()
        }).TotalSeconds
    }
    catch [Exception] {
        $dur = "unreachable"
    }
    Write-Output "$dur`t$mirror_url"
}


# Become proxy aware.
(New-Object System.Net.WebClient).Proxy.Credentials = [System.Net.CredentialCache]::DefaultNetworkCredentials
[Environment]::SetEnvironmentVariable("NO_PROXY", "127.0.0.1", "User")

# Parallel measure each mirror latency.
purge-any-pending-job
$max_threads = (Get-WmiObject -Class win32_processor).NumberOfCores
$mirrors = ((wget https://cygwin.com/mirrors.lst).Content -split "`n")
$total = $mirrors.Count
$jobs_count = 0
foreach($mirror in $mirrors){
    if($mirror.Length -eq 0){continue}
    Start-Job -Scriptblock $measure_mirror_latency -ArgumentList $mirror | Out-Null
    $jobs_count++
    Write-Progress -Activity "Verifying all mirrors..." -PercentComplete (100 * $jobs_count / $total)
    While ($(Get-Job -state running).count -ge $max_threads){
        Start-Sleep -Milliseconds 30
    }
}

# Wait for all measuring jobs to finish.
While ($(Get-Job -State Running).count -gt 0){
    Start-Sleep -Milliseconds 100
}

# Get each measure results.
$results = @()
$jobs = Get-Job
foreach($job in $jobs){
    $result = Receive-Job -Id ($job.Id)
    $results += $result
}
purge-any-pending-job

# Return the fastest mirror.
(($results | Sort-Object)[0] -split "`t")[1]

Remember to use one PowerShell terminal to run it.

If you want to run it in a regular command prompt, wrap its code inside a .bat file this way:

@ECHO OFF
powershell -Command ^
"^
Put here all the fastest_cygwin_mirror.ps1 code lines, each one terminated with ;^
"

já tentou usar o mobaxterm?

Hum... Dá para usar em ambientes "hostis" de rede? ;)

Acabei de olhar o MobaXterm... UAU! Muito obrigado pela dica!