I usually use 10 watts with my Protank. I tried lowering it down if you've seen me say that in my above posts, but there's no luck. I'm just curious how no one has this problem.
The problems are generally with the stock wick and coil assembly. I scratch the silica and use cotton wick instead, have been building my nova's for a long time this way with no problems. Many tutorials all over on it, very easy, simple fix. Use silica if that works for you, just better to rebuild in general. One of the main things (you'll see in the tutorial) is cutting slots in the plastic head to let more juice through. Your problem sounds like a wicking issue, your getting nasty dry hits = not enough juice getting through.
Check out pbusardos old review and rebuild and of the vivi nova, watching his massive fingers recoil is an inspiration in how easy it can be. He also talks about some of the general issues with these things.
One other thing I would mention is the difference between the vision and the smok vivi nova's. Lots of issues with the smok, vision was considered the better of the two. If your stuck with the smok version you may be sol. Look at stock pictures comparing the two to figure out which ones you have.
All in all it's practice practice practice. The initial phases suck in figuring out how to work with a new unit when they don't work well fresh out of the box (an issue for many with the vivi's). But if you read through many of the threads on the fixes and follow the video tutorials and work on it, you can have a superb vape in no time. Then rewbuilding them will come very very easy and natural and you'll be in thw onderland of vaping.
Recap:
Both and neither. SVD was set to high, always start low and work your way up. Different juices can stand up to higher watts - some enhancing flavor - sometimes burning it. Different juices gum up your coils quicker and become burnt.
Wick assembly is your main problem.
(regarding the fact you used 10 watts with the protank) All units (protank, BCC, RBA's etc) are a different beast entirely. I vape my BCC's at around 6 watts and my top coils closer to 8 watts. They'll never be the same because the build structure is completley different. With each new unit you must learn a new set of designs (in rebuilding) and have different ways to vape it (output power of your battery), you may need to use a different battery completley. Many variables in the vapeing world.
I rebuild vision vivi novas with cotton candle wick and 32 gauge kanthal wire with about 6 wraps giving me 2.4-2.6 ohms resistance. I put a piece of cotton ball on top of the coil assembly for extra juice saturation. Let it soak in a full tank for a few hours minimum (overnight preferred). Then load onto my SVD starting at 6 watts, eventually making my way up to around 8 watts. Awesome vape.
Google "A PBusardo Tutorial - Vivi Nova Cleaning & Rebuilding" for an easy rebuild to follow along.
**One more important edit**
Generally I've had more luck with lower content VG juices in the vivi nova. Partly because I use cotton wicks are generally better at holding liquid then transferring them. There's a longer distance for the juice to travel in a top coil assembly like the vivi hence the better performance of higher PG liquids. When talking clearo's, bottom coils with shorter wicks generally work better with higher VG juices as the short wicks can easily stay saturated. I'd recommend higher PG (I prefer 70/30) in your vivi in general, and especially if your to rebuild with cotton.
. So I'm using a Vivi Nova tank with 2.4 ohms and i put Cold Turkey's Gary's Cherry liquid into the Vivi nova. The SVD reads 2.7 ohms and it gives me a horrible taste, burning taste. I don't know how to fix this so i though i would come on here and get some help. Thanks guys 
