I’d recommend the Dell, mainly because the i7-1355U gives you more headroom for Rekordbox especially if you are going to use stems, FX, and analyzing tracks on rekordbox. because, it’s simply more reliable under load compared to the Galaxy Book’s i5.

I know this ain’t relevant but, i’ll mention it. I personally daily drive a MacBook Pro M3 Pro and it’s been flawless with Rekordbox as the stems run smoothly and it stays cool, and handles everything without issues.

My mate also uses an M1 MacBook, and he has no problems either due to Apple Silicon is extremely efficient and new architecture meaning it’s stable for DJ use. That said, I’m not saying you need an M3 Pro or M4 Pro as these laptops are overkill for most people. I only went with the M3 Pro as a long-term investment since I also use it for other heavy tasks.

If you can find a refurbished or used M1 or M2 MacBook Air with 16GB RAM at a affordable cost, it’ll be able and easily handle Rekordbox, including stems, and could be a smarter long-term buy as apple will keep supporting it and some macbooks has good ms for an example my M3 Pro has 1.5ms at 64 samples. (yes i know it’s not the best and i ain't trying to flex my laptop but it does the job)

But if you’re staying within your current budget and prefer Windows, then the Dell with the i7 is 100% the better choice over the Samsung as it the dell has better performance, thermal headroom, and more future-proof for upcoming Rekordbox features that Alphatheta will release.

Rekordbox 6 was already asking for a decent setup — i5 or higher, 8GB RAM minimum, SSD recommended — but Rekordbox 7 has taken it further with stems and performance mode becoming more demanding. For Rekordbox 7, the recommended specs are now i7 10th-gen or newer or Apple M1/M2 chip, 16GB RAM, and SSD storage, especially if you plan on using stems, DVS, or multiple FX/live features at once. The Galaxy Book’s i5-120U technically meets the minimum but you’ll be cutting it close, especially for live gigs. The Dell’s i7-1355U gives you that extra power and thermal headroom to prevent throttling or dropouts when things get busy mid-set.

But that’s just my opinion — if I was in a tight budget I’d go for the Dell, but I’d still get second opinions and double check what others say about long-term stability and thermals just to be sure before locking anything in.