Here is the comparison for the average temperature in a cosmological simulation.All codes are using the 4th order scheme for the potential gradient.

Cholla is using PPMP HLLC and SIMPLE, .

Now using Cooling and UV Background:

Power Spectrum

Here is the power spectrum for Cholla and Enzo without using Cooling/UV:

and :

These where the parameters that best matched Ramses: Gas is much colder.

Now using Cooling and UV Background: