how important is latency

[junkone]

i have dual wan. both start cable and primus dsl. i have noticed that last week, my cable internet thro start became very slow when i connected it via the tp link dual wan router.

so i made it a single wan with start cable to troubleshoot and found it was very slow. my google drive forms updates were constantly failing.

here is the latency tests that i did. the latency seems to be very close between start and primus.

does this latency explain google drive being slow?

 

[sinshiva]

well, latency certainly affects responsiveness, but not your throughput. i'd bet latency comes into play more when transferring directories of small files, though

is that the closest speedtest server to you?

 

[junkone]

when i use the primus speedtest i get
Last Result:
Download Speed: 5102 kbps (637.8 KB/sec transfer rate)
Upload Speed: 649 kbps (81.1 KB/sec transfer rate)
Latency: 19 ms
18/1/2014 22:57:36

But i cannot explain why my google docs are slow

 

[azazel1024]

It could be because of painfully slow upload speeds. Not sure how much data needs to go upstream for Google docs doing things, but ~80KB/sec is pretty slow.

19ms is fairly low latency, but the 120 odd ms ping response time in your screen caps in the first post are very high.

latency WILL reduce maximum bandwidth. The higher the latency, the slower the actual transmission rate. With TCP/IP anyway. You have to send Ack packets periodically for the sending machine to send more data to you, so if your latency is high, you get shoved a bunch of data, but then it sits there waiting for an ACK packet before sending more.

High latency means once your machines gets its spurt, it sends and ACK...but then there is a bunch of latency, the ACK packet gets there and then the other machine sends you more. That latency adds "dead link" time where there is no Tx going on and you lose usable bandwidth.

You might have 5Mbps, but if you have super high latency, the USABLE portion of that might be a fair amount lower. That goes double for the really slow upload speed.