During the stress testing for our review of the Lenovo Flex 3 11 we noticed some great results from this little notebook. It features Intel Pentium N3540 (4-core, 2.16 – 2.66 GHz, 2MB cache) CPU and a fanless design. The temperature under normal load is around 50°C and after an hour and a half of our standard 100% CPU load test the temperatures rose to just 66-68°C which is a really great result for a fanless notebook and far away from the maximum operable temperature Tj.max (100 degrees). We also have to note that there was no throttling during the test and the CPU frequency was between the standard 2.16 and the boost 2.66 GHz.
After these surprisingly good results came the hard truth for the underpowered CPU with integrated graphics card. You will not be able to do much, if any graphical work as right after we started the 100% GPU load along with the CPU stress test the processor speed throttled down to just 500MHz and the laptop was barely usable. Aside from the throttling the Flex3 1120’s temperature remained normal and even dropped a little to 64 degrees after another hour of CPU and GPU stress, that could be explained by the significant CPU throttling.
Another good news for the Flex3 1120 is that there was no excessive heat over the keyboard or palm rest and it was comfortable to work after a long period of stress testing. You can see the results on the heat map above.