AMD is seeking to ease concerns over what appear to be high temps on its Radeon RX 5700 series graphics cards. In a recent blog post, AMD said a temperature reading of 110C during a "typical gaming" session is both "expected and within spec."
This might be higher than what you are used to seeing. According to AMD, it's not that Navi cards necessarily run hotter. Instead, triple-digit temp readings could simply be the result of the new cards utilizing a bunch of sensors spread out over the entire GPU die.
"Paired with this array of sensors is the ability to identify the 'hotspot' across the GPU die. Instead of setting a conservative, 'worst case' throttling temperature for the entire die, the Radeon RX 5700 series GPUs will continue to opportunistically and aggressively ramp clocks until any one of the many available sensors hits the 'hotspot' or 'Junction' temperature of 110-degrees Celsius. Operating at up to 110C Junction Temperature during typical gaming usage is expected and within spec," AMD explains.
In essence, the Junction reading represents the hottest part of the GPU. Where exactly that is at any given moment can vary, based on what you are doing and what part of the GPU is hit the hardest.
Using an array of sensors in this manner ultimately enables Navi cards to offer "much higher performance and clocks out of the box," and do it at reasonable noise levels, AMD says. Meanwhile, Navi cards also still provide average GPU temp readings, in addition to the Juncture temp.
The blog post goes into more detail and is worth checking out when you have the time. That said, the upcoming crop of custom 5700 XT and 5700 cards by AMD's hardware partners will undoubtedly result in lower temps, by way of burlier axial cooling solutions.
In my experience, third-party GPU cooling solutions also tend to run quieter than blower-style coolers. Just be sure your case has adequate airflow if going that route, or else you end up circulating hot air inside your PC.