Which PC should I get? One with 3080 or one with 3090 for $400 more?

I just returned an Alienware R11 with a 3090. I had an i9-10900k CPU and had cooling issues.

The processor would run 90+ degrees and throttle causing stutters.

The only way to prevent it wad to turn off hyperthreading.

In my opinion the Alienware has a small cramped case with insufficient cooling.