Denoising, in general, is not very smooth unless you are lucky or you have a very powerful GPU and computer specifically created for rendering fx. Because you are on a laptop, as already suggested, it would be much, much better to apply the effect in After Effects and then export a single clip back to Premiere (which will become your new master clip). It seems like a whole lot of trouble, but denoising is a very serious thing. I've accomplished this on my laptop with success, but it was very slow. The native effects in AE take a lot of time and the 3rd party effects such as DeNoiser and others can be worse. To summarize, avoid the dynamic linking with Denoising or Denoising directly in Premiere if you don't have a powerful computer.
As a side note, for future, difficult exports, try less compressed, higher quality formats such as Prores, DNxHD, DNxHR, Go Pro Cineform, or Animation. Recently, we had some issues with particle effects in animation and we tested output in various formats across different computers and it was clear that some formats put additional pressure on the effects processing. Effects cause a lot of processing and if you combine a highly compressed file format...this can mean longer processing times and more things that can negatively affect the output. Some effects have issues with even the mighty Prores file format. There are times where GoPro Cineform and Animation seem to process smoother. I'm not saying this is the perfect answer to your problem, but this is something to be aware of or try on a lower powered machine.
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