Can anyone recommed a good download optimizer?

Hi! I´m Mirela, from Argentina.

I was wondering if any of you can recommend a powerful download optimizer (for downloading files from FTPs faster).

I translate movie scripts, and I generally log on to my clients´FTPs in order to download movie files to assist in the translation, and these are extremely heavy (more than 600 MB and even more than 1000MB).

I have broadband internet (cable, 1Mbps), but even so the transfer rate for those movie files I mentioned is 33KB/sec, which is too low for me.

I am not currently using any download optimizers. I tried WS_FTP Pro, but it didn´t help much, the transfer rate did not improve significantly. And I need to make downloads faster.

I´ve been doing some research, and found three download optimizers which seem to be quite good according to users´opinions: 1) Free Download Manager 1.45; 2) Fresh Download; 3) Robust FTP.

Can anyone tell me which would be faster and better (most important of all: free and without ad or spyware)?

Thanks in advance,
Mirela
Argentina