Same on ATI R9 290 - GPU temp monitored in realtime increases constantly with long range scope or binoculars until either crash to desktop or throttling from GPU.

Have to use zoom sparingly and can see temp increase and decrease as I zoom and then don't zoom.

If you face a town all objects inside your view volume are loaded. (The view volume is the space between the front and back clipping plane.) This means all objects, players, zeds etc. are loaded even if they are behind the walls or buildings. During the process of creating each picture the GPU has to calculate whether you will see the object or not. So even if you will not see the objects on the final picture on your monitor all objects are loaded during the process of creating the picture. (60 fps equals creating 60 pictures per second.)

The more objects there are in the view volume the more calcuclating your computer has to make to create a picture. The more calculating the less FPS you will have.

Here is a link if you want to have more information about the view volume:
http://viz.aset.psu.edu/gho/sem_notes/color_3d/html/rendering.html

Same issue here.

GPU load goes to 100% immediately and stays there for as long as you look at a distant place. GPU temp increases accordingly, up to the point where safety circuits kick in, artifacts appear (pink blotches on ground, black lines along the 3D path of shadows) or the whole PC crashes. Didn't notice any impact on FPS outside the usual variance. CPU load slightly but noticeably decreases on 2 of 4 cores (by about 10%), the other two stay the same.

I've played the game with 2 Geforce GTX 570s (different models, DxDiag is for the latest, most stable one) and a Radeon HD 5750 so far, the issue is the same on all of them.

The issue seems dependant on zoom level, unzoomed scopes don't cause it all, zooming with eyes has a mild effect and looking through binoculars has a very pronounced effect. Looking at cities seems to have no greater or even a smaller effect than looking at fields and forests. Looking around in the distance has no different effect than looking at one place all the time. The bigger the area in the distance is, the bigger the effect is, regardless of how much of that area you can actually see through the binoculars without looking around. The biggest effect so far for me has been just outside Dubrovka, looking north east towards the gas station.

CPU load is usually 70%+-20% per core for me, GPU load is usually 40%+-10%.