because vertic ur not blocking vents its just a faceplate horizontal u block 2 of the vents but the focus of keeping the heat down is just not blocking the back fan vents thats were the heat get vaccumed out.

alot of peoples overheat prob is cuz they use inter cooler laptop coolers 360 pushes heat out all thoes things do is push the heat back in thats 90% of rrod if witnessed was stupid cooling methods.