AMD Ryzen 7 7840U 8-Core Zen 4 Laptop CPU Breaks Cover In Benchmarks Looking Strong
AMD's Zen 4 processors can display remarkable performance-per-watt once they've been manually tuned, or if you enable ECO mode in the system setup. You lose some multi-core performance, but the power consumption of the chip drops drastically. That could explain what we're seeing with some leaked benchmarks for what is purportedly a Ryzen 7 7840U laptop processor.
In the main benchmark, Cinebench R23, the leaker on Weibo dropped a single image showing a multi-core score of 14,825 points for the eight-core CPU. By our reckoning, that comes in just behind a Ryzen 5 7600X, and indeed slightly behind the eight-core Zen 3-based Ryzen 7 5800X. While that might not sound impressive, remember that those desktop processors have beefy cooling and 105W or higher power limits.
Meanwhile, this mobile processor with its "U" designation should have a power limit of 28W or less. That means we're seeing 105W eight-core Zen 3 performance out of a low-power mobile chip destined for thin & light machines, and that TDP is shared with a large RDNA 3 graphics processor, too—something that neither the 5800X nor the 7600X have to contend with.
Another curious note is that the base frequency of the CPU appears to be 3.3 GHz. That's quite a high base clock for a "U" series CPU, but as we noted in the intro, Zen 4 can be quite efficient at lower clock rates—and for a CPU that might boost as high as 5 GHz, 3.3 GHz isn't very high at all. It also makes it clear that this is a different CPU from the Ryzen 7 7840HS, which we saw leaked before.
The leaker includes some other benchmark scores, and we don't have our own data to compare unfortunately, but looking at the 3DMark Fire Strike result database on UL's website, the Radeon 780M's listed 3DMark Fire Strike graphics score of "about 8000" puts it in the same general region of performance as the very fastest Radeon 680M parts.
If you're not familiar with the Radeon 680M, that's the GPU built into AMD's extant Ryzen 6000 family. The fastest benchmarks on the chart come from Ryzen 9 6900HX CPUs. Those are mobile CPUs with a "default TDP" of 45W, but gaming laptop vendors are free to crank the power limit. It has a strong RDNA 2 GPU with 6 WGPs running at up to 2400 MHz, and we found it to be perfectly serviceable for 1080p gaming.
If this ultraportable CPU is matching AMD's fastest integrated graphics in pre-release form, that bodes well for the Phoenix IGP's gaming chops. We're extremely curious to see what these chips can do for ourselves, so look out for a review once we get our hands on one.