For a couple of years now, AMD has offered special versions of its desktop processors with an extra 64MB chunk of L3 cache included. This cache is layered on top of the existing CPU silicon, earning it the name "3D V-Cache," and it has proven especially successful for accelerating cache-sensitive software like games.
Today, AMD is announcing the first 3D V-Cache processor for laptops, the Ryzen 9 7945HX3D. It's a version of the regular 16-core Ryzen 9 7945HX with that same 64MB chunk of cache added in, giving it a total of 144MB of L3 cache.
The 7945HX is essentially a version of the desktop Ryzen 9 7950X repackaged for use in laptops instead of high-end desktops; while chips like the similarly named 7940HS use one monolithic silicon die for everything from the CPU cores to the chipset to the integrated GPU, the 7950HX uses a pair of 8-core CPU chiplets and a separate I/O die.
By the same token, the 7945HX3D is a mobile version of the Ryzen 9 7950X3D for desktops. The 3D V-Cache is layered on top of one of the CPU chiplets, giving it eight cores with access to the extra cache and eight cores without it; AMD's chipset software is responsible for making sure the "right" cores are used for any given task, to the extent that the non-V-Cache cores can be parked entirely when a game is running. (In our testing of the 7950X3D, the software worked as advertised, though as with many heterogeneous CPU architectures, there have been hiccups.)
One of the fringe benefits of the 7950HX3D was also lower power usage and higher efficiency since the CPU die with the cache stacked on top needed to be run at a lower voltage to prevent overheating (we don't know whether this is also the case in the 7945HX3D, but it seems likely). AMD says the 7945HX3D's performance advantage over the regular 7945HX increases as the processor's TDP is reduced; at 45 W, the 7945HX3D can be up to 23 percent faster than the 7945HX in games. At 70 W, the 7945HX3D has a smaller 11 percent performance advantage. AMD says you should expect it to be about 15 percent faster in games than the 7945HX on average.
For now, the 7945HX3D will only launch in a single laptop: a version of Asus' ROG Strix Scar 17, which launches on August 22. AMD said that the ROG Strix Scar would be the only 7945HX3D laptop "for the foreseeable future," though presumably any design that currently uses a 7000-series HX CPU like the 7945HX should also be able to use the 7945HX3D with minimal changes. The configuration AMD tested with includes 32GB of DDR5 RAM and a mobile Nvidia GeForce RTX 4090, which will make this one of the fastest (if not the fastest) gaming laptops you can buy, though, as with any gaming laptop, your performance will be limited a bit by power limits and temperature ceilings.
AMD didn't say what the 7945HX3D version of the Strix Scar 17 would cost, but the safe answer is "more than $3,300," which is the current street price of the same laptop with a 7945HX in it.
If that price makes you cringe, AMD has more budget-conscious X3D processor options for desktop buyers. Last month, the company announced a Micro Center-exclusive Ryzen 5 5600X3D, an upgrade targeted at owners of older socket AM4 Ryzen systems who want a budget-minded performance boost without having to upgrade to a newer AM5 system (or buy a fancy new laptop).
Listing image by AMD/Andrew Cunningham