@nadineabdoun Without knowing the specs of your Mac, I can't say for sure whether the HP laptop would run Sims 4 better. But if you have anything other than a 15" MacBook Pro (so a 13" Pro, or any Air or any plain MacBook), then the HP is likely faster for gaming. Its graphics chip can run Sims 4 on medium-high to high settings, even with all current packs installed.
I will say that you'd be better off not running anything else alongside the game while playing on this laptop. 8 GB is enough for Windows and Sims 4, but not much else, at least not on a laptop with integrated graphics, as this one has. But then you have your Mac for anything else you want to do at the same time.
When I wrote about internal storage, I meant in reference to a possible new computer, not upgrading your current one(s). For the external SSD, it would work with either system, but you'd need to format or partition it to switch OSs. If it's working now with the Mac, it's likely formatted as APFS or MacOS Extended (Journaled), neither of which Windows can use. For Windows, only NTFS and possibly exFAT/FAT32 would work. Macs can read exFAT, but Sims 4 .package files won't work on an exFAT drive, at least in macOS.
All of this is to say, you can't simply plug your external into your Windows laptop and expect the data to be read. You'd need to either format the drive, thus erasing its data, and start over; or you'd need to partition it, if it has sufficient space to do so, and transfer the files. That seems like a lot of effort given the current size of your cc collection.
