AMD’s Ryzen 9 7945HX3D brings speed-boosting V-Cache to gaming laptops

What do you get when you combine AMD’s fastest mobile processor, Dragon Ridge, with its killer performance-enhancing desktop technology, 3D V-Cache? The AMD Ryzen 7945HX3D, which AMD claims to be the world’s fastest laptop gaming processor.

It’s a claim that AMD can back up. The Ryzen 9 7945HX3D performs substantially faster than the existing 7945HX, the flagship “Dragon Ridge” processor AMD announced at CES 2023 in January. In general, the 7945HX3D’s performance ranges from about equal to the 7945HX to a stunning 44 percent to 53 percent faster for games like Cyberpunk 2077 as well as Riftbreaker.

Essentially, AMD’s 3D V-Cache takes a giant chunk of cache RAM and mounts it to the top of the CPU die, using a modular architecture called chiplets. The additional cache stores frequently accessed instructions close to the main CPU die. If a game needs to access those instructions, the larger at-hand cache means that it can do so quickly. Otherwise, it would have to search for them from the PC’s main memory. Put extremely simply, it’s the difference between keeping a serving bowl of food on the table at dinner, versus walking into the kitchen for additional helpings.

AMD’s Ryzen 9 7945HX3D appears to run at the same frequencies as the 7945HX: 2.5GHz base, or up to 5.4GHz while boosted. Like the 7945HX, it’s a Zen 4 chip. The 7945HX3D contains 16 cores and 32 threads, while operating at “55W+” thermal design power, according to AMD. (AMD specifies the 7945HX at between 55 and 75W of power.) The key difference, of course, is the cache: a total of 144MB of cache, 64MB more cache than the 7945HX.

Gamers or laptop makers don’t have to run the 7945HX3D at full power. AMD shared a slide showing that the chip can improve performance by 22 percent at just 40W, and by 11 percent at 70W, compared to disabling the V-Cache entirely. (At the lower power, the V-Cache allows the 7945HX3D’s CPU output to catch up to the discrete GPU, putting them more in sync and increasing overall performance compared to the 7945HX, an AMD spokesman said. At 70W, the additional power helps the 7945HX catch up, lowering the performance improvement that the V-Cache provides.)

It’s the games, though, where the additional performance will matter. Here’s how AMD sees the Ryzen 9 7945HX3D stacking up to the 7945HX. (You may need to open the image in a separate tab and zoom in to see the fine detail.)

In most cases, the additional V-Cache translates into increased performance.

AMD

The Ryzen 9 7945HX3D joins the Ryzen 5 5600X3D, Ryzen 7 5800X3D, the Ryzen 7 7800X3D and the Ryzen 9 7900X3D and 7950X3D as AMD’s sixth 3D V-Cache processor.

The new chip will feature inside the ROG Strix Scar 17 X3D, a new gaming laptop that will launch on August 22, AMD said. According to leaked product listings, discovered by Hot Hardware and others, the laptop will boast an RTX 4090 GPU, plus 32GB of memory and a mammoth 2TB SSD. The ROG Strix Scar 15 we reviewed in 2022 included a 240Hz 1440p display, so we can expect at least that in the new model.

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