Im having trouble with video lag. I suspect it's because of my processor (2.8Gh i5) I was wondering if anybody has tried running this title from an external SSD.

Are you currently running it from an external SSD? If so, what interface did you plug it into. A USB 2.0 interface will bottleneck an SSD.

No. It will make no difference.

The delays are caused by your CPU being held up doing other things.

The only solution is to reduce the load on your CPU.

Witcher 3 is notorious for the load it puts on all CPUs. The higher you make your in-game settings, the more load.

Mine for example can handle max with ease, no delays at all. But my CPU does get incredibly hot and my CAM reports excess of 80C every so often, especially in Novagrad.

The only solution is to reduce the loading.

Make sure nothing else is running. Turn off all updaters, ( should be done anyway), think about rescheduling your virus checker's scanning and so on

In Video settings, I reduced the frame rate to 30, There is a lot of misunderstanding about frame rate. In reality, the video we see on TV is between 25 and 30 FPS. https://en.wikipedia.org/wiki/Frame_rate

Next I reduced the crowd to minimum.

I turned off NVIDIA Hairworks.

Finally, in the section Video > PostProcessing, I turned off all the settings.

That reduced the loading considerably.

In your case, this is were to start. Try these as a beginning. Then continue to reduce things in the video settings until you get a smooth experience.