Just because you jump on a much faster internet, doesn't mean scrapebox will perform faster.
You need to first go into the scrapebox settings and increase the threads for different processes. Find a sweet spot. Don't just max out everything either. I have a really fast freaking internet, and I use 40 threads for the fast poster, and 50 for proxy checking. When doing processes that actually analyze the content on a website (blog analyzer, outbound link checker, ect.) I know it still has to load the website in the background. I run about 30 threads for this. If you max these out, you could get a lot more errors.
So tweak the SB threads and find a good working balance.
Also, if your computer is a POS, then that is a huge problem.
You could have the fastest internet in the world, but with a shitty computer it could feel like your on dial up.