Video Editor Rendering - 7 hours to render 22 mins of video / audio I've got what I think is a rendering issue and despite reading and watching many things on here and the internet in general, I can't fathom it out.

Firstly, I'm quite new to blender video editor and have only been using it for about 3 or 4 months now but am really enjoying using it.  I've rendered several videos on it all and from what I can remember, all seemed to go fine.

However, the last few videos I've edited and rendered (all circa 20 mins) have taken between 6 and 7 hours.  I have no idea if this is considered good or bad, but no mater what changes in blender I make, nothing changes regarding the render time and was wondering if the fine people on here could assist me please. 

The last video I created in there was a combination of 2 video + audio files and 1 audio file.

Video 1 is a 22 min long game footage capture from my xbox one via an el gato HD60 capture device.  This video and audio is then soft cut into smaller sections in BVE with the audio being lowered on some of the cuts.

Video 2 is an 8 second long intro video + its audio with no adjustments.

Both of these videos are setup on the same strips while the 3rd file (audio only MP3) is setup on it's own strip.

The specs for each file and my hardware are as follows....

Video / audio 1:
22 mins long
.M4V
1920 x 1080
59.94 FPS
Stereo
48 kHz

Video / audio 2:
8 secs long
.MOV
1920 x 1080
59.94 FPS
Stereo
48 kHz

Audio file :
22 mins long
.MP3
Stereo
44.1 khz

Blender settings / output details:
Memory Cache Limit - 4gb on the laptop / 32gb on the PC
Interestingly, no mater what I set it to, BVE only seems to use half of it, however, again, no mater what I set it to in terms of size, it doesn't make any difference to the render time.

Dimensions:
1920 x 1080 (100% scaling)
59.94 FPS

Anti -Aliasing, Sampled Motion Blur, Shading: 
All off

Performance:
Threads auto detect

Output:
H.264 RGB

Encoding:
MPEG4 H.264
Bitrate 6000

GOP size 30

Audio codec MP3
Bitrate 384

Hardware details:
PC -
Dell Precision T7400 
Windows 10
56GB RAM
2.5ghz Xeon Quad Core CPU
AMD Radeon HD 6000 series (I think) (1gb)

Laptop - 
Macbook Pro Early 2013
OSx 10.10.3
8GB RAM
2.4ghz i7
Geforce GT 650M 1gb
SSD

Something to note is that everything is being done from / to a WD Elements USB HDD (IE all blender and original video / audio files are on the drive + rendering to the drive), but this has always been the case, including on the earlier videos which seemed to render fine.
I've also tried rendering from the USB HDD to the PC SSD but there is no difference in time to render.

Hopefully there is enough info in here, but if anyone requires any more info, please just ask. :)
I Really want to keep using BVE for now as I've only been video editing for a short time and can't afford the bigger / more professional packages out there. :(
If you are rendering anything on the stock USB 2.0 ports, you should expect slow times.  You could get either a USB 3.0 or 3.1 card for your box or move all of your files to an internal media drive and work from there.