A good, free tool to check CPU and GPU heat?

I use GPU-Z to check the temperature of my GPU. In the past I would use Everest and Aida that could check both, but currently I don't care about CPU temp or fan speed :D

SpeedFan.

MSI Afterburner

I usually use HWMonitor.

I use MSI Afterburner's OSD to display all of the above and more.

psensor

HWMonitor

Everest

AIDA

http://openhardwaremonitor.org/

hwmonitor !

CPU temperature - CoreTemp, RealTemp

MSI Afterburner.

speedfan? I used it a long time ago, it's the only one I know of.

I'm a fan of speccy myself.

HWMonitor or speedfan. What works better for you.

i am using AIDA64. it is shareware so I am not sure about the demo. But you can see everything...temperatures of your CPU, HDDs, GPU. All information about your system (even how many times you booted your system) and much more.

HWMonitor and SpeedFan, as have been mentioned, are great.
I use Core Temp for CPU, and MSI Afterburner, because both can be set to output to the LCD panel on my Logitech devices.

Speccy, by Piriform.
Gives you your computer's specs and temperature.

for cpu: coretemp
for gpu: gpu-z

meh idk i just used cpuid hw monitor or something like that

Open Hardware Monitor

Real temp