SSD odd issue

[Infamous786]

Hello, I have 3 machines that have SSD, My main pc is Samsung 830 256 gb which runs as normal, My Sony Z series laptop has my old OCZ Vertez 2 120 gig, and my mrs laptop is a Samsung series 9 laptop which has a sandisk SSD, the issue I have is that when I transfer files from my NAS via filezilla, both laptops slow down while transferring files, this is via wifi. This does not happen on my main pc, just wondering if this was normal?

 

[Infamous786]

My main pc, is a 2600K clocked to 4.5 ghz, with 8 gig ram. The samsung series 9 laptop is a
i5 1.6ghz, which i would have thought would be powerful enough. My sony z series is a 2.5ghz core duo, the laptops transfer about 17-20 meg bytes a second from my NAS, I was thinking could it be the Antivirus slowing things down, I have had this before with a Symantec AV, but I use Esnet Anti virus on all 3 for many yrs.