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Extremely wonky / mostly slow download rates while updating

GerZah
over 8 years ago
Hi,

I just came over from this thread over in the Windows section – that I somehow couldn't respond to.

Anyways: I'm about to install a map update on my my nüvi 765 through the latest Garmin Express / Mac software. I know from previous updates that the "last mile" through the USB cable is painfully slow – I suspect that it is using USB 1 speed. So I know that 4 GBs over that cable take 3 hours or something like that. Can't be helped.

However: The download speed is incredibly wonky. I'm here on a 50 Mbps DSL line which works flawlessly. No other download clients are active, typical download rates are 5-6 MB per second. This way, a 4 GB = 4000 MB download could be done in like 4000/5 = 1000 seconds, i.e. roughly half an hour, give or take.

This being said: The downloader stated that the download alone would take about 8 hours. My status bar told me that it was drawing about 150 KB/s. While trying to accept my fate, over the next half hour, it suddenly reported something like 6 hours. Huh.

While I am typing this, there was a short phase in which it actually sucked 6 MB/s out of the line, so the ETA timer gradually stepped down to about 1h15m … And after having written that very previous sentence, download speed has dropped back to sometimes 200 KB/s, and the ETA is back up to 5 1/2 hours. … I didn't take screenshots, so you'll just have to believe me this.

Well. This is rather frustrating. I can definitely rule out complications on my end. Garmin, what you need is to invest into some properly functioning content delivery network. This is really a huge bummer, which seems to have been the case for years and years, judging from the above mentioned posting.
  • 0 over 8 years ago
    … I cancelled the download and switched over to a VPN connection that I use for various reasons, mostly to work around geo blocks. In this case, I didn't switch countries, but stayed in my home country. This approach has often led to success in similar scenarios (e.g. sometimes iCloud and other Apple data traffic is slow). And also in this case, the map update download was indeed finished after less than half an hour, and the update installation is about to finish while I am typing this.

    Ultimately this means that Garmin's download servers were not in fact overloaded, but the problem arose somewhere along the way. Often these are DNS issues –*so if someone reads this: Please try to switch to a different free DNS server, which might improve performance.
  • 0 over 8 years ago
    DNS is involved only at the very beginning of a transfer when the host’s “domain name” (the ‘D’ and ‘N’ in DNS) are translated to an address. Given the fact that all computers will time out on those requests (usually on the order of tens of seconds), the impact that DNS response time can have on overall transfer rate, especially for very large files, is quite limited.

    However, by using your VPN you undoubtedly forced a very different route for data between Garmin’s server(s) and you and that can obviously have a profound affect on overall transfer rates.
  • 0 over 8 years ago
    Well, umm …

    First of all: Sure, a VPN connection creates a whole different route, nothing to argue there.

    But secondly: As for DNS, while it doesn't sound logical that a changed DNS server should change transfer speed, indeed it often does – especially for services like Google or Apple. I didn't fully understand the reason, but if you check e.g. www.google.com via one DNS or via another, you will probably see different or sometimes even more possible IP addresses – so traffic directed through one DNS server might lead to data streams from different servers through different nodes within the same content delivery network.

    I can confirm from personal experience that I could "heal" slow traffic speeds from Apple iTunes (i.e. rented movie streams) on multiple occasions by switching to a different DNS server. … For example, see this case. I could switch back and forth DNS, and at the same time provoking slower or faster speeds.

    That's why I recommended to try different DNS servers first and shoot the bigger guns like trying VPN connections to achieve different routes later.