Note that the working_set_min set to 70% in your case will cause qlikview to start emptying cache whenever it hits 16,8GB. If, as in your case, you use up to 19 GB on average then I'd recommend you raising the working set min to 85% instead which is just above 20 GB.
And yes the HyperThreading should be set to off, but.
Try changing the working set min and post the results.
I'd tried raise the working set to 85%, but there is not a significant affect to the performance. When the memory is up to 20 GB, the performance (loading time / calculation time) become slow again. Is there are any practise/way to optimize load my qvw on access point? Is I need to raise my RAM capacity?
Yes that would be the effect once your application usage hits 20GB plus.
Adding more RAM might be the answer. Sure you'd keep your speed up to the new limit, but it seems that your application consumes quite a bit of RAM. For a 1,6GB application to grow to 20GB it's quite a big growth, a factor 12,5 which is somewhat high. I assume that the 1,6 GB size is measured shortly after a reload.
What's the amount of RAM shortly after reload and how fast does it hit 20 GB.
What do you have to do to reach that?
If I was you I'd take a look at how many objects/charts per sheet the application has.
Does it have any large pivot/straight tables that are always drawn.
It's recommended to use show/calculated conditions to limit the amount of CPU/RAM used with every qlik.