Hi,

Firstly I want to start by saying that this issue is not solely a problem with the Phantom 4 Pro as I've always had the same problem with Phantom 4 footage.

When I import all my footage from the Micro SD card and import to Sony Vegas 13, the video preview is choppy and lags, however when I play the video in VLC, it is fine, but as I wanted to edit my footage in Sony Vegas, VLC is no help to me. I was originally trying 4k footage, so I thought maybe the laptop can't cope with 4k footage, so I tried recording 1080p24 and still the same happens. I have a Dell XPS 15 loaded with Intel i7, 16GB RAM, Nvidia graphics card so I don't see laptop specs being an issue here.

I'm hoping someone here can offer a solution as I have hunted Google, watched many Youtube tutorials and no 'solution' works for me.

Well, Vegas 13 has issues.  One huge one is any video recorded higher then 1080p will show as choppy in the video preview panel.  One trick is to press SHIFT-B to do a prerender of the video footage.
Also note: unless you have a solid GPU card, your video playback will also be choppy.

Sometimes, editing in Sony Vegas gets really choppy when playing back the video. To avoid that, a fast system with good processing power, higher capacity rams and faster hard drive will make playback video much faster. However, it's very expensive. In this tutorial, you will see how to avoid choppiness at no extra cost.

Steps

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  1
  Open Sony Vegas.
  
  
  
  
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  2
  Drag any video clip to the time line below that you think will cause choppiness when playing a video in Sony Vegas.
  
  
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  3
  Play the video.
  
  
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  4
  If you find the video lags, highlight the empty time line.
  
  
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  Press Shift + B.
  
  

Had you said the issues were in Vegas 12, I would have said to upgrade to a newer version of Vegas. I had issues with ver 12 as it apparently did not support all the codecs that 13 and 14 do. Once I upgraded to 13 (then 14), all my stutter problems went away, and I do not need to render previews at all. I can even run intense effects in preview and they run perfectly. Just my experience though.

i think is an issue of editing software, i have noticed it hapening with corel x8 as well. since the computer doesnt have a hardware decoder to playback 4k, then the playback is intensive for the processor, thats why it lags. is a defeat of the purpose of actually seeing what youre editing, but it also means the software is good at post-processing rather than real-time playback.

The preview screen, being what it is shows a pre render view with all affects set in the editor being applied in real time. This requires a huge amount of processing power, and is primarily dependent on having a fairly powerful graphics card. If the editor is set to use this GPU (Graphics Processing Unit) for processing this can vastly improve the preview image.

What edition intel i7 do you have? Also, what Graphics card?

Aardvark Posted at 2017-2-7 10:18
The preview screen, being what it is shows a pre render view with all affects set in the editor being applied in real time. This requires a huge amount of processing power, and is primarily dependent on having a fairly powerful graphics card. If the editor is set to use this GPU (Graphics Processing Unit) for processing this can vastly improve the preview image.

As an aside to this, Sony Vegas has been broken for several versions in terms of correctly using the GPU (if present). This has been discussed ad nauseum on the Sony Vegas forum. If I remember correctly, it requies a GPU card with heaps of CUDA cores, but does not take advantage of OpenCL, which is the more modern system. Much as I love Vegas, I have given up on it and now use Resolve, even though the current version does not have the same features as Vegas.

With regard to laptops, real power in video processing requires more than a laptop will deliver. Computational power translates to speed and therefore heat. Laptops cannot cool themselves sufficiently to handle intensive video.

It's not due to the resolution but video codec probably.  Phantom 4 Pro can bring us h.264 and h.265 codec, which is not idea for editing. Now check solution here:

How to Work Phantom 4 Pro video in Sony Veags.

The graphics card can make a huge difference to the preview lag, a lot also depends on what video effects you have applied. Some are more GPU friendly which can help. In the preview window it is applying any changes you have made in real time which is intensive. I can testify to this as my preview was always a bit lumpy using a GTX650 card even with all preview settings low. The opposite was true with a GTX 1080 TI where all was set to max', with preview viewed full size on a 4k screen there were still hesitations at times, but only just.
One way round it (I use movie studio 13, The little brother of Vegas) is to set "Automatically create video proxies for Ultra HD media" in the preferences. Although this can take a while depending on file length, perhaps a few hours, (you should see a progress bar in bottom left corner of window) it effectively produces a lower res' version (the proxy, which runs a lot smoother) for editing and preview, whilst applying any changes to the final 4k project.