A/B testing involves comparing the conversion rate of your original web page against the conversion rate of its variations. A variation is a modified version of your original web page. These modifications in A/B test variations can range from small text changes to a complete design overhaul. 

You can run an A/B test between one original and n variations. These are served to an identical audience at random, and the one with the highest conversion rate is the winner.

A Split URL test follows the same philosophy as A/B test. The conversion rate of the original and the variations are compared to find the highest value, which is declared as the winning variation. 

The difference here lies in the magnitude of change that you make in the variations.

If you're making minor changes to elements' HTML, then you should consider running an A/B test. The changes done in the A/B test using visual editor are implemented from CDN server to the web page you have configured. These changes are made live on the original URL using the PageSense tracking code.

However, for a complete redesign with a lot of changes, it may be faster to recode the page. In such cases, each page is hosted on its own URL. Here, when you have to compare multiple pages with distinct URLs, you must go with a Split URL test.

Keep in mind that testing is all about comparing the performances (conversion rate) of variations. To draw an accurate comparison, you'll have to change the same element in each variation. You should also avoid making too many changes between the original web page and its variations. Stick to making a few important or radical changes, so you'll be able to understand the reasons behind the success or the failure of the test. In the long term, running iterative and structured tests will lead to a sustained increase in conversions.