Laptops, no matter their specs, are not powerful in the real World. first, mobile hardware ALWAYS is weaker per the specifications. Second, they have terrible cooling. the CPU and GPU will thermal-throttle when you load them for any longer time.
the listed clock speeds of processors depends on power delivery, and temperature. If one is not sufficient, the clock-speed will be reduced to use less power and produce less heat. So your 4GHz CPU you paid a lot of money for, only runs at 2.5 GHz. At that point you could have saved the money and bought a 2.5 GHz CPU for example. Imagine you you have a Ferrari motor and a Corolla cooling system. You can use the Ferrari fast for 2 seconds, then you have to slow down. that is what happens with the CPU/GPU. If you only need power for a few seconds, that is fine. If you need sustained power, it will be a problem.
There also is RAM speed, not just the amount. and how it matches the CPU RAM speed options. Slow RAM can limit you with a powerful CPU since the CPU will starve of data, or will not be able to move data back to RAM. There is a reason those box-Pcs don't tell you what RAM they use.
A PC is larger and has inherently better cooling. But many of the pre-built PCs still are not great in that regard. cheap cases, too few and cheap fans etc.
another problem with pre-built are cheap power supplies and motherboards. there is a reason they list which CPU, but not which board they use. Besides longevity, the board has the CPU power delivery and that can be insufficient and over-heat.
You may look into a computer forum for specific advice. You can steal the BIM-box specs regarding GPU and CPU and use that as a starting point.
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