Intel had a lot to prove to the market with the last two laptop lines, Lunar Lake and then Arrow Lake mobile. And while the desktop chips were disappointing, the laptop ones showed a great balance of efficiency and performance. Now it's time for the new generation to launch, with Panther Lake. Instead of two series, Intel Core Ultra 3 Series has a single line, blending the best bits of Lunar Lake and Arrow Lake into a (hopefully) harmonious whole.

So, can Panther Lake be both efficient and powerful? Well, I've been using the superb Asus Zenbook Duo powered by the Intel Core Ultra X9 388H for a few weeks now to try and answer that question. The new cores are snappy and have plenty of power. The battery life is even better than I expected. The new Xe 3 GPU cores are the best iGPU I've used, and even better than some discrete options. Intel is first out of the gate with this year's mobile CPUs, and has set a very high bar for both AMD and Qualcomm to follow, and that's without considering that Nvidia's N1X laptop chips are around the corner. It's going to be a very exciting year with some fantastic laptops coming out.

About this article: Intel sent XDA an Asus Zenbook Duo powered by the new Intel Core Ultra X9 388H mobile processor for review. Neither company had any input on the contents of this article.

Price, specs & availability

The first wave of Panther Lake laptops is out now, from HP, Dell, and MSI, but you can bet Lenovo is not far out. Samsung and Asus both have units available outside of North America, but we're waiting for pricing details on the US and Canadian launches. These are not going to be cheap, so expect a modest increase over last year's Lunar Lake for a similarly tiered laptop when they're more widely available.

So far, we've seen the Dell XPS 14 with an Intel Core Ultra X7 358H starting at $1,599, HP's OmniBook X starting at $1,449 with the same CPU, and the slightly larger Dell XPS 16 starting at $1,749. We're waiting to hear the price of the Zenbook Duo we reviewed, but last year's Zenbook Duo with Arrow Lake's 285H inside was $1,800.

What's new with Panther Lake?

Efficiency is the name of the game, and a new iGPU

The Intel Core Ultra X9 388H is the flagship of Panther Lake, with 16 cores and threads, a P-Core max boost of 5.1GHz, and 12 of the new Xe3 graphics cores in the Arc B390 GPU. With four performance cores and eight efficiency cores, this CPU also has four low-power efficiency cores to keep things ticking over when you don't need the extra grunt. That should translate into improved overall battery life, and if it can improve over Lunar Lake's efficiency, that'll be an impressive feat.

The new Xe 3 cores feature multiframe generation through Intel XeSS 3, and more graphical power for creator tasks and gaming. This is the first series of chips on Intel's 18A architecture, which promises Arrow Lake Mobile's power scaling alongside the efficiency of Lunar Lake. This CPU has eight PCIe 4.0 lanes and four PCIe 5.0 lanes, which isn't many to go around but likely enough for the ultrabooks that it's intended to go into. This isn't a desktop chip, those are coming later when Nova Lake reaches our shores.

The good

What a chassis to show off this new chip with

I've been falling in love with the Asus Zenbook Duo over the last few weeks, both for its versatility but also for the performance that the Panther Lake CPU brings. It's always a fun time when it's a new mobile chip, and it could be anything from a basic clamshell to a 2-in-1 convertible or ultrabook, but this year it's even more fun.

This review unit has the Intel Core X9 388H processor, 32GB of soldered-on LPDDR5 RAM, and two 14-inch, 3K OLED touchscreens. It also has another party trick: the physical keyboard lifts off, turns into a Bluetooth keyboard, and lets you choose a second screen for apps or a virtual touch keyboard.

Now, two displays is hard to drive for many graphics chips, let alone when at 3K resolution. The new iGPU in this Panther Lake chip is a belter, and even with both displays running at 144Hz, it never skipped a beat. This is a premium laptop, and will cost significantly more than last year's model, but that's true for every piece of tech right now.

The versatility of this convertible is unmatched: either as a clamshell with the keyboard attached, or as two screens in vertical or horizontal orientation, enabling you to work on one screen and read on the other, or watch YouTube, or chat with your friends. I normally struggle on a single laptop screen, as I'm used to dual ultrawides, but I didn't find I missed them as much with a second screen. The physical keyboard and touchpad are on the better end of those I've used recently, and the virtual keyboard and touchpad are usable, but I'm not sure why you'd want to use them.

Time for some benchmarks

We've been saying the same things about every laptop tested over the last year: AMD has the best CPU, Intel has the best iGPU, and Qualcomm and Apple have the best battery life. It's been a fantastic year for choice, and now it's even easier.

The Intel Core Ultra X9 388H is not only the best iGPU, but it's the best CPU, and the most efficient Windows laptop I've tested. It's even on par with MacBooks for battery life, something I didn't expect to be saying. Intel has set a high standard for anyone to follow this year, and I'm excited to see what the rest of the Panther Lake lineup can do once it arrives on my desk.

Laptops can often perform very differently when plugged in and on battery power, with Windows 11 power plans and manufacturer software packages changing things as well. It makes a little difference here, but not as much as we've seen in previous generations. Lunar Lake often drops performance on battery power, but Panther Lake is closer to the drop than Arrow Lake, with almost the same performance.

I've had no issues with running photo editing apps, using a variety of AI-powered editing functions, and doing some video editing. The rendering performance of Panther Lake seems to be a regression, but every other aspect of my workflow has been snappy and smooth.

While running Procyon's battery testing that plays various videos with Media Player on a loop, the Zenbook Duo with Panther Lake's Intel Core Ultra X9 388H only used 4% after an hour. That's on pace for 25 hours of video playback from a dual-screen ultralight laptop. That's impressive, and if Intel can bring that level of efficiency to the rest of the lineup, it's on for a winner.

Oh, and we can't forget about testing that new iGPU. Cyberpunk 2077 is often a system killer, but at 1080p High and XeSS Super Resolution 2.0, it averaged 68 FPS. That's 3x the FPS that the Arrow Lake iGPU could manage, and on par with many mobile dGPU chips. And it looks superb on that HDR 1000 OLED screen.

The bad

Thermal throttling is still an issue

I don't remember the last time I used an Intel CPU that didn't have some level of thermal throttling, but it's also true that modern silicon is designed to run to its thermal limits, then throttle down slightly to stay under the safe limits. And that's exactly what this Panther Lake chip does: it boosts until one or more cores hit 97C, then eases off the throttle somewhat to stay at that mark. I noticed it was often the efficiency cores that were the hottest, while the performance cores were a few degrees cooler at all times.

However, that doesn't appear to affect performance one bit, whether it's productivity or gaming, and at no time was the laptop's lower screen or keyboard uncomfortable to touch. The thermal solution Asus has designed has plenty of vents for airflow and performs well overall.

Should you buy a laptop with the Intel Core Ultra X9 388H in?

You should buy the Intel Core Ultra X9 388H if:

• You want the best iGPU available for light gaming
• You need all-day battery life
• You want to use Windows 11 instead of macOS

You should NOT buy the Intel Core Ultra X9 388H if:

• You need more than 32GB of RAM
• You want a more affordable solution

Once again, Intel is starting the year off on the right foot. Panther Lake's flagship processor is efficient, powerful, and the pairing with the new Xe 3 GPU cores makes it a viable option for on-the-go gaming. You don't have to go for the snazzy Asus Zenbook Duo to get the Core Ultra X9 388H, but if the convertible life appeals to you, I highly recommend it. This is one fun laptop, in a sea of boring gray rectangles, and I've completely fallen in love with it.

I know I said there are some thermal issues, but that was mostly under sustained loads or gaming, where you'd expect the CPU to get warm. Every gaming laptop I've used for the last few years has been similar, and this is an ultrabook that isn't even supposed to have enough power to run games well. The integrated Arc B390 GPU is stunning and delivers stellar performance in games I didn't expect it to run.