Question i5-1335U vs i5-13420H

[dddaviddd]

I bought a Lenovo V15 G4 IRU laptop with 16 Gb RAM and 512 Gb SSD.
It should come with an i5-1335U but instead it came with an i5-13420H.
I want to understand the differences between those CPUs.
Some questions:

1. They went to market at the same time (Q1'23) and almost at same price (342 $ / 340 $) so I guess they must meet very different targets otherwise I would see no point in marketing both.
2. GPU: I read that the 1335U's Iris Xe (80EU) is better than 13420H's Intel UHD 13th (48EU) but I see that on 3DMark it looks like 13420H is faster so I do not understand (https://www.notebookcheck.net/i5-13420H-vs-i5-1335U_14729_14916.247596.0.html)
3. PassMark overall CPU Mark and many others see 13420H slightly faster in multicore and almost identical in single core (so I wonder why should someone buy 1335U at the same price?)
4. PCIe: 1335U PCIe version 4.0 with 20 lanes while 13420H PCIe version 5.0 with 28 lanes. Could you explain what does this impact?
5. TDP: hugely different, 1335U 15 W and 13420H 45 W. I am puzzled here: since technology is very similar (10 nm and equal project age) I guess efficiency is almost equal so it lools like the 13420H is only capable of dissipating more heat, just in case? But when you set power settings to consume less power they should consume more or less behave the same. So I guess there is no difference in battery life: the 13420H is only *able* to consume more. Am I missing something?

 

[satrow]

Simple terms:

U = basic, slow, (underpowered).

H = full-fat but heavier on battery. You can 'de-tune' it when you don't need the extra speed/heat.

PCIe 5 enables most internal components to work faster, maybe also more efficiently, than PCIe 4. (thus the extra speed over the U seen in some benchmarks.)

I'd opt for H every time, it's something of a bargain at the same price as U.

 

[dddaviddd]

Thank you for your reply!
As per your answer, I understand there is no reason to prefer the U if I set the power options to save battery.
Though, I still have some dubts on point 2 (GPU).

 

[satrow]

U is usually cheaper, not usually in direct competition with H, cost differential/performance is too great.

If the CPU runs faster, it drives the GPU faster, too (similar with RAM). Given that the PCIe 5 specs allow greater throughput as well, there's no doubt in my mind that the H would run the GPU just as fast, likely faster, than the Iris in the U CPU.