Panther Lake's limited number of PCIe lanes means you probably won't see any gaming laptops arriving with the 12-core Xe3 iGPU and a discrete GPU
You've read my breakdown on the architecture behind Intel's new Panther Lake processors. You've gone through every graphics benchmark that Andy has done with the range-topping Core Ultra X9 388H. Between the two of them, you've now decided that your next gaming laptop is going to be Panther Lake-powered and sport a big GPU from Nvidia, to go with Intel's big Xe3 tile. You're possibly going to be disappointed, then, to know that you're almost certainly not going to see any such lappies coming to market.
The reason why is quite simple: it all comes down to the number of available PCIe lanes in the platform controller tile. Intel has two variants of this chiplet: one with 12 lanes (four are Gen 5, eight are Gen 4) and the other with 20 lanes (eight Gen 4, twelve Gen 5). The important thing, though, is that every Core Ultra 300-series processor that has the big 12-core Xe3 iGPU uses the 12-lane platform controller tile.
AMD and Nvidia's mobile GPUs are designed to use at least eight PCIe lanes. That doesn't mean you can't fit a discrete GPU alongside a 12-lane PTL chip; it's just that it will leave just four for everything else inside the laptop. The majority of NVMe SSDs require four lanes, and you obviously need a storage drive, so that's all the lanes gone.
While those dGPUs can operate with fewer, it's not something that laptop vendors are likely to explore, because it would be leaving performance on the table. Not very much, granted, but you wouldn't have the issue with the 4-core Xe3 PTL variants, or Intel's Arrow Lake mobile chips, or AMD's Ryzen processors, either.
Even if you used all eight Gen 4 lanes for a dGPU, that would leave just four lanes behind, which an NVMe SSD would swallow up. With no other PCIe lanes available, there would be scope for a second M.2 slot, and more importantly, no Thunderbolt 4 ports in the laptop (as these also use four PCIe lanes each).
However, Panther Lake does offer quite a bit of flexibility when it comes to the configuration of the 12 PCIe lanes in the Core Ultra X9 388H. The four Gen 5 can be used as x4 or two lots of x2. Those eight Gen 4 lanes are actually two bundles of four, and each of those can be set up as one x4, two x2, or four x1.
Which means, theoretically, one could have a dGPU using the four Gen 5 lanes, and then having the M.2 slots and Thunderbolt ports just get by with two lanes. But that's far too messy to be dealing with, when a laptop manufacturer can just go with a 4-core Xe3 PTL processor, a discrete GPU, and still have plenty of lanes left over.
I think Intel has missed a trick here. If it used the 20 PCIe lane platform controller tile across all Panther Lake SKUs, then these pocket rockets would be on par with the obvious competition: AMD's Ryzen AI 300 and 400-series.
These all sport an iGPU of varying sizes and are happy to be paired with a discrete graphics chip. Leaving Strix Halo aside for the moment, the top-of-the-pack Ryzen AI 9 HX 475 has a Radeon 890M iGPU, with 16 RDNA 3.5 compute units, roughly 33% fewer shaders than the 12-core Xe3 tile, and it sports 16 Gen 4 PCIe lanes.
Eight of those will be taken up by a dGPU, of course, but that still leaves plenty of lanes left over for two M.2 slots. Since the APU itself natively hosts two USB4 ports, you don't need to worry about having some spare lanes to attach fast peripherals.
Admittedly, with every gaming laptop I've ever used, I've never once felt the need to use the iGPU if it had a decent dGPU. Some laptops will switch between the two to save power in desktop mode, but you don't need a 12-core Xe3 iGPU to watch a movie or do battle with a large spreadsheet.
So while a daring laptop manufacturer could shoehorn a Core Ultra X9 388H together with a mobile RTX 5080, you're probably just going to see a horde of 'little Xe3' variants instead. When AMD is able to offer you the best of both worlds, it's a shame that Intel can't or won't as well.