OK , so I downloaded the AI Gigapixel v2 - 31 day free trial version, so I could compare it with my current resize image software - PhotoZoom Pro 6.1 (that I paid a discounted price of only $20 for a few years back).
I enlarged/resized 2 of the same photos (1 with a resolution of 180 DPI - 1000 pxls x 800 pxls to 400% larger, and the other a 300 DPI image of 1200 pxls x 900 pxls to 600% larger) using each program.
My Windows 7 Pro computer system (more than a few years old now) is only just above the minimum requirements and the AI Gigapixel v2 worked faultlessly, with no issues at all.
The results were outstanding and impressive, in favour of AI Gigapixel, which was better all round, I must say!
I only used the default settings in AI Gigapixel, with the 'Reduce Noise and Blur' on Moderate.
It took 3 mins and a half for the larger size (600%) to be processed and the newly resized imaged saved automatically.
With the PhotoZoom software it took just over 2 mins to process the larger size, however, the quality and clarity/detail was not as good as the AI Gigapixel (nor was the 400% enlargement).
Hopefully, this Topaz product will be on special soon, as I definitely recommend this software as the best for enlarging images for posters or to become large artworks to hang on the wall.