quality of telemetry and cpu speed/cores number

My suspicions are that the 4th screen is taxing your GPU's by way of insufficient video memory. However the 6 core upgrade will help ease your bottleneck by way of allowing your system to process data quicker so that will only be a good thing. I do suspect thought that you may have to acquire a better graphics card (like the gtx970). you could try to SLI the cards and see what happens I suppose. Try it and see....

Don't run a slower card dedicated to physx as it will slow down your 760. Ideally you should run two cards that are the same. If two cards are on the same PCI bus they will run at the slowest cards speed. In your case I am suspecting that the 760 is running at the 250 speed. Use msi afterburner to monitor memory frequency and card utilization. Test speeds and utilization with only the 760 in and then test with both cards. Hope I'm wrong cause it could mean you've wasted money. I thought the 760 could run four displays anyway?

Forgot to write:

1. 45 degrees seems really low heat, check MSI that your GPU if being fully utilised
2. Single card systems are the easiest to set up, sli require your motherboard to be made for SLI so there's an added cost.
3. Do your homework and chose one card that will support what you want to do. Using 2 separate GPUs cause trouble. SLI would be better than two separate cards but not as straight forward as one GPU.
4. As above, dedicating a card that is slow to physx just slows down your main card as it waits for the slow card to complete its operation.

thanks i will go to high end card gtx 970 probably and return to the store the cheap card . i loose some money but not that much ...

I can certainly couch for the gtx 970. Expensive though. Just make sure the model you get has the correct video connections you need.

Hello
here are some updates.
i upgraded to a six core amd cpu vs 4 before. the gaming was drastically improved especially in rfacor2 (+ peripherials and motion)
so it seems that the bottleneck was the cpu or maybe the thourough cleaning for dust, and new thermal compound on the cpu (i dont know)
after testing i also switched video cards )same card with twice as much memory . the fps was improved significantly...
i run only one card now i guess it is better for the air flow . I was thinking to use maybe another cheap card for the data screen to aleviate the load on the main graphic card {going back to my original setup ...)? what do you think?

thanks for the good advice to all of yous