Please, make the 600x600 preview view faster for FF 6.0 and 300x300

Now that it is already 64 bit what it really would make it a even more excellent software and be at the same level as many others is that the reduced 600x600 preview is made faster (or much faster) than it is now to make it much more usable.

Each time that you modify any setting it must render again the image, and there many times that that this may take between a few seconds, 15 seconds or even a minute or much more depending on the filter you may be using

Could we have maybe a 300x300 preview mode on a checbox option? As a super reduced preview, for some specific custom settings where the quality of the image may not be important, this could be useful and helpful

For the full image result there are already some external renderers that you can leave unattended and will work and do the slow work for you, but what is important and essential is to be able to use the preview faster

If FF could have Preview acceleration, OR have some kind of big improvement in the render speed in whatever way, it would be the greatest reason to upgrade and would sky rocket the sales of FF and it would be much more popular, as it is recognized as an awesome and amazing software BUT slow to render and also to preview any changes you make in the settings

Yes, this could be a good idea to be able to have alternative preview sizes rather than only 600x600

Following the suggestion of Skybase, I think that it could be done to have 3 preview sizes instead of 2

1 - Reduced - 600x600

2 - Custom - You decide what resolution you want to use in the preview

3 - Actual - is the final result that is already configured in real size when saving the render

MAKING A FASTER PREVIEW

I have thought about how FF works, and the preview as far as I know, is using the same render engine to make it and there is no difference or special thing made for the preview, just reduced the render size, and the same happens for the thumbnail presets that they are also created using the main render engine

So I do not know if there could be some way to make faster the preview without modifying the main render engine.

Maybe it could be made a separated preview engine as other graphic software have made so you can have a fast preview, and then when satisfied and right, you click to render the final result that will be slower, or any other possible way that may be good

Thanks