Old models of the ThinkPad-E-series often had issues with high temperatures if you got a configuration with a dedicated graphics card. The manufacturer sometimes even issued a patch that would reduce the performance significantly to ensure lower temperatures (see review of the E480, for example).
The new ThinkPad E15 can also get pretty warm. We have just finished our temperature measurements for the ThinkPad E15 with the dedicated Radeon RX 640 GPU and from what we can tell so far, the cooling solution is once again not appropriate. Simultaneous load for the processor and the graphics cards results in a massive drop in CPU performance (clocks between 400-900 MHz), but the case temperatures at the bottom still reach almost 70 °C. This is the area of the cooling solution, but the hottest spot is actually at the support foot. The heat picture shows a slightly higher value at almost 74 °C, but we still got 68.7 °C (~155 °F) via contact measurement.
Our stress test is obviously an extreme scenario, which is not common for a business laptop. However, you might be tempted to play games on the device after work if you get a model with a dedicated graphics card. So we also performed our Witcher 3 test. The CPU load is a bit lower, but we were still able to measure surface temperatures of around 65 °C in this practical scenario.
We will continue our tests and present the final results including benchmarks in our full review. However, we definitely recommend you avoid any skin contact (not put it on your lap) when you stress the ThinkPad E15.