Since everyone is complaining about the naming schemes of CPUs, I'll pitch in.
An Intel Core Ultra 7 155U and a Core Ultra 7 155H, are very different classes of CPUs!
If you're comparing laptops, you'll see both listed, and laptops with the U variant will be significantly cheaper, because you get half the max TDP, 4 fewer cores, 8 fewer threads, and a worse GPU.
This isn't to say the 155U is a bad chip, it's just a low-power optimized chip, while the 155H is a high-performance chip, and the difference between their performance characteristics is a lot larger than you'd expect when looking at the model numbers. Heck, if you didn't know better, you might text your tech-savvy friend "hey is a 155 good?", and looking that up would bring up the powerful H version.
Their laptop naming scheme at least is fairly straightforward once you figure it out.
U = Low-TDP, for thin & light devices
H = For higher-performance laptops, e.g. Dell XPS or midrange gaming laptops
HX = Basically the desktop parts stuffed into a laptop form factor, best perf but atrocious power usage even at idle. Only for gaming laptops that aren't meant to be used away from a desk.
And within each series, bigger number is better (or at least not worse - 275HX and 285HX are practically identical).
Don't forget the V series in there. I have an Intel(R) Core(TM) Ultra 7 258V in my Thinkpad. I think they're still being made. I bought an open box Thinkpad T14s Gen 6 with it - they come with a nicer GPU than the Ultra 7 255U.
The V series is a one-off thing Intel did, but they don't have a direct successor planned.
Previously, they had a P series of mobile parts in between the U and H series (Alder Lake and Raptor Lake). Before that, they had a different naming scheme for the U series equivalents (Ice Lake and Tiger Lake). Before that, they had a Y series for even lower power than U series.
So they mix up their branding and segmentation strategy to some extent with almost every generation, but the broad strokes of their segmentation have been reasonably consistent over the past decade.
Very interesting. I was a bit out of the loop on Intel mobile CPUs; I looked up the benchmark specs for it when purchasing and saw that it generally trounces the 255U.
I've been really quite happy with it - most of the time the CPU runs at about 30 deg C, so the fan is entirely off. General workloads (KDE, Vivaldi, Thunderbird, Konsole) puts it at about 5.5 watts of power draw.
An Intel Core Ultra 7 155U and a Core Ultra 7 155H, are very different classes of CPUs!
If you're comparing laptops, you'll see both listed, and laptops with the U variant will be significantly cheaper, because you get half the max TDP, 4 fewer cores, 8 fewer threads, and a worse GPU.
This isn't to say the 155U is a bad chip, it's just a low-power optimized chip, while the 155H is a high-performance chip, and the difference between their performance characteristics is a lot larger than you'd expect when looking at the model numbers. Heck, if you didn't know better, you might text your tech-savvy friend "hey is a 155 good?", and looking that up would bring up the powerful H version.