Currently running a 5900x/3090/32GB RAM/32" 1440p monitor system. Also have an XBOX Series S in my living room. I play shooters with an XBOX Elite Controller.
I run Fortnite on both. I do go back and forth but mostly play on my PC. Every other game I play is on my PC. Age of Empires, Sim City 3000, FTL, Fall Guys, MS Flight Sim and a few others that I start and never finish.
I would ask yourself will the games you play lend themselves to PC. For example I load into Fortnite itself much quicker than my friend on PS5. I can crank my settings up and see very high detail at 60 FPS or turn them down and run 120-240 FPS. Right now I have my Series S running at 120 FPS and my PC running at 120 FPS. The PC kills it in visual quality.
Another advantage I have with PC is I have more settings I can play with. The biggest one is turning off shadows, which cannot be turned off on XBOX. Enemy hiding in the shadow on XBOX, cant see them. On PC, there is no shadow so I see them just fine. I am sure there are more settings in Fortnite that lend a hand to PC players at the expense of console players. I am sure there are other games which may have similar situations where settings favor PC.
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As for people talking about games running on PC vs Console. I have not had any major issue with either. I had issue with AMD GPU drivers, once I switched to NVidia that problem went away.
Also the library of games on PC is huge compared to Console. I can play a game from the 70s up to any current release.
I can also emulate a lot of Console systems if those games aren't natively on PC.
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What I would do if I was you is set up your desk area. Even if you stay with Console and get a laptop your wife will appreciate having an area to use the laptop. Then I would buy a nice monitor. Decide what size you would play on if you have a gaming PC and buy that monitor. 27" and up.
Set everything up and then move your XBOX over and play on the PC monitor for a few weeks. If you like the feel of playing at a desk versus the couch then I would move forward and start looking for a PC or components to build the PC you want.
If you choose to stay with the XBOX and playing on the couch then you can return the monitor if you want or plug the laptop into it and a wireless keyboard and mouse so your wife can use it when at home and disconnect when wanting to be mobile.
Personally I find I play more competitively at my desk than I do on my couch. I think it's mental that I've tricked myself into being more aggressive at the desk.
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Dell recently had a 13700/4090/16GB RAM XPC PC for $2000. Yes, the system is slightly lopsided towards the GPU and lacking elsewhere. But that is just to show you that you can get a prebuilt PC with quality components for about the price of the video card itself.
The price is now $2500
4090 system
They also have a similar system with a 4060Ti for $1100
4060Ti system
Not perfectly balanced system but a decent value in both systems. Especially if the 4090 comes back down to $2000.
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No you don't need a $1,000 video card to be competitive. My gaming buddy was playing with a $400 3060Ti and wiping lobbies with ease. Basically that $1100 Dell system above but a generation older.
My 3090 will be relevant in mainstream gaming for a few more years. Right now my once top tier card is about the same as a mid tier current gen card. In the next generation it'll play like a lower end card, which is still a playable card. The following generation will show my card's age and it'll play like some budget cards.
The best example is the 1080Ti.
A card from 2017 that still beats NVidia's 4060 That is 7+ years of playability and relevance.
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Gaming Laptop vs PC.
First, laptops are much more susceptible to breaking. Whether it be from dropping, spill, crushing, it will experience a much tougher life than a PC under your desk.
Second, if something breaks on your laptop you could be out of luck fixing it cost effectively.
Third, upgrade path. You cannot upgrade core components the same as a PC (yes, storage and sometimes RAM are upgradeable.) My system has evolved over time. Which if you plan ahead when building a system you can have a less expensive upgrade path. I am still using my case that is over 10 years old. I am still using my motherboard from 2017. I am on my 3rd CPU upgrade and 4th video card upgrade. (I was mining Ethereum in 2020/2021 and had a lot of different cards to play with.)
Good luck deciding.