Soldered RAM doesn't really run hotter.

No, soldered RAM doesn’t significantly affect thermals. The heat from RAM—whether soldered or socketed—is negligible compared to the CPU and GPU. The real thermal design concern with soldered RAM is that it can force the RAM chips closer to hot components like the CPU package, but that’s a layout choice, not a property of soldering itself.

In practice, the difference in temperature between soldered and socketed RAM is less than a degree or two. If a laptop runs hot, it’s because of the cooling system (fan, heatsink, paste), the processor’s power draw, or the chassis design—not because the RAM is soldered. Most ultrabooks with soldered RAM run fine thermally, often better than thick gaming laptops with socketed RAM because they prioritize a larger cooler.

Where soldered RAM hurts is upgradeability and repairability, not heat. If you’re worried about thermals, focus on the laptop’s cooling solution and how well it handles sustained loads. Soldered RAM is a non-issue for heat.