@Vedran both nvidia and amd are semiconductor stocks and they are very expensive, but they are not in an identical position.
nvidia is already TINA in high end graphics, their gains are mostly from cloud AI/compute expansions, and they can basically charge what ever they wish to for their high end cards.
AMD on the other hand has just a “slice” from the gargantuan CPU market, in all segments and there is huge opportunity for them to gain. This is not a “futuristic” view or vision. There already is an established market, if Player A does things better for cheaper it’ll get a bigger slice from the pie. Forward P/E is just “price / forecasted earnings” which is not enough alone to call it a buble (imo)
AMDs market share is 19.2%/19.9%/5.8% for desktop/mobile/server CPUs respectively. As long as intel keeps lagging there is a very realistic potential for AMD to double and triple its market share. Although this is not a duopoly AMD/Intel cover the vast majority of CPUs.
This is very true, it is a slow moving market and building momentum takes time and trust by OEM partners. But there are already signs of tides shifting, starting with the consoles. Dell, HP and Lenovo only started partnering with AMD in 2017 it has been like token 1-2 models per brand up until early 2020. They just started offering multitudes of models (especially after the success of mobile Ryzen 9 4000 series)
Then again, I have an average price of $20.5 for my current AMD holdings, so its a bit easier for me to cheer for AMD. 
