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Why are my multithread test results always slower than single thread?


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Mine are always about 25-40% slower.

From the description of Mutithread test here on TMN: "Enabling the multithread speed testing option on your download speed test can really open up your connection for maximum throughput."

It doesn't matter what time of day I choose. Typically I would select the Wash DC and Dallas servers. When I add the west coast servers, it's even slower.

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As the multithread test involves transferring lots of small files, I wonder if it is taking an unusual amount of time to establish the individual connections or if something is briefly pausing the start of each individual transfer.  For example, some antivirus products scan the data at the start of each transfer to check for known infections and this sometimes causes a brief pause before allowing further data to download.  I had issues with AVG in the past causing unusually long delays when downloading files.


If something is briefly delaying each connection, then this would likely cause the multi-threaded test to take longer as instead of a brief pause in a single transfer, there would be a brief pause in every individual transfer of the multi-threaded test, so with the 50 or so small files downloaded during the test, these pauses probably add-up more than any speed benefit of running batches of transfers simultaneously through the test.


If you can easily disable your antivirus product or firewall, I would suggest trying the multi-threaded test again with these disabled.  The issue could also be within the ISP if they are doing something like deep-packet inspection on each connection that is established. 

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Thanks for the response. I don't have any 3rd party protection software, only what is built into Mac OS 10.9.5. That and whatever is built into my old D-Link DI-604 router. When I set it up, I didn't do anything special. Not sure if Time Warner is doing anything different during the Multithread testing. For single thread testing I almost always get slightly above their advertised 50/5 plan speeds.

I'm not sure the slower multithread testing results are telling me anything about my performance in real world web page loading. Whenever the single thread test results are at or near the 50/5 maxes, I get good web surfing response except for site that I know are always slow.

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That would raise my eyebrow... 


It's not your connection... it's the computer somehow.  Your iPad has seen 55 Mbps in multithread.  I'd also first go off of the classic single thread test, if that's faster... the connection is faster.


I would suspect from your results that pages are loading slower.  But it may not be noticeable.  If it's not bothering you... don't worry about it.  When it's the other way around and your multithread results are MUCH faster... then it's more cause for concern.  Personally... it would drive me nuts until I figured out why it's doing that.  Because it's not normal unless the computer (CPU) or browser can't keep up with the intensity of the multithread test.


Like editorsean, I would question something that may be post processing the information in your browser.  I've seen 3rd party software and malware screw with results like this.  It will become apparent in the multithread test because the issue becomes compounded by the volume of elements.  ... could be that the elements actually download quickly but each one takes a lot of time to initiate.  If it lags the test... it lags your page loading.


Here's from my 2011 iMac... same as I get on my Late 2014 5K iMac.  


Classic [db link]






Pretty similar to your computer... you should have similar results.  Well, at 50 Mbps that is.


Your iPad has pulled better speed so we know that your router, modem and ISP aren't to blame.

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Well I tried Firefox vs Safari using Multithreading tonight. They both had very similar results. Both were a little slower than the single thread tests by about 20% maybe. I did the tests during peak hours - about 10:30 PM. My single thread results were only about 35 down where they are usually at 50 during off-peak hours. The Multithread tests were in the 28 Mbps down range.

My plan has a 5 Mbps upload max which I was reaching during Combined testing tonight. Is it possible that the 5Mbps up limit comes into play more during Multithread testing and slows the process down?

My mid 2010 iMac is only an i3 processor, but with nothing else running I wouldn't think that it would be the bottleneck. But I don't pretend to understand the Multithread process and how much it taxes the main processor.

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