Can you post a link to the monitor you're talking about?
For most gaming, an IPS monitor would be fine as long as you don't mind the slightly higher response times they have compared to gaming specific monitors. Normally, an IPS panel will have a response time of between 5-10 milliseconds, and a gaming-specific TN panel will normally have a response time of 1-2 milliseconds.
Unless you're a professional gamer who seeks every advantage in online competitions, it isn't really necessary to get a gaming specific monitor with a super low response time. IPS panels will have much better viewing angles and color accuracy compared to TN panels. So if you're not a professional gamer and also intend to watch movies on your monitor from time to time, an IPS monitor would be a better choice.
The resolution of a monitor usually does not affect its speed or response time. However, some 4K monitors are restricted to 30Hz refresh rates, which means you will only ever get as high as 30 frames per second in everything you do with it, and that is not really acceptable for gaming.