compatibility of Quadro P5000 and Titan RTX on the same workstation

I am planning to buy a new workstation “HP Z8 G4 for NDNA”. For our 3D data analysis and visualisation, we need to install two different graphic cards in this workstation. I plan to use one Quadro P5000 (for real-time visualisation) and the second one Titan RTX for computations. I have just learnt that these cards are not compatible with each other on the same workstation. Could you please clarify this? If this is the case, could you please suggest any other computational GPU (with similar specifications and price), which can be installed along with Quadro P5000?