Intel 11th-generation Rocket Lake-S gaming CPUs did not impress us

Enlarge / Our test rig is a little more unlovely than usual, due to Asus’ decision to entomb the CPU socket in surrounding high-rise heatsinks, with the system’s RAM closing in just as tightly from the bottom. (Note the empty pair of DIMM slots.)

Jim Salter

Today marks the start of retail availability for Intel’s 2021 gaming CPU lineup, codenamed Rocket Lake-S. Rocket Lake-S is still stuck on Intel’s venerable 14 nm process—we’ve long since lost count of how many pluses to tack onto the end—with features backported from newer 10 nm designs.

Clock speed on Rocket Lake-S remains high, but thread counts have decreased on the high end. Overall, most benchmarks show Rocket Lake-S underperforming last year’s Comet Lake—let alone its real competition, coming from AMD Ryzen CPUs.

Our hands-on test results did not seem to match up with Intel’s marketing claims of up to 19 percent gen-on-gen IPC (Instructions Per Clock cycle) improvement over its 10th-generation parts.

Multithreaded CPU performance

It shouldn’t come as an enormous surprise that Core i9-11900K underperforms last year’s Core i9-10900K in multithreaded tests—this year’s model only offers eight cores to last year’s 10. If this part had shown a 19 percent improvement in IPC, that might have come out to a wash—20 percent fewer cores, balanced out with 19 percent higher IPC.

What we actually saw was noticeably decreased performance across the board. Cinebench R20 and Passmark scores are each down about 10 percent. Geekbench 5, which tends to minimize the impact of higher thread counts, shows an alarming 27 percent gen-on-gen performance decrease.

This year’s Core i5 makes a much better showing than its Core i9 big sibling. In Cinebench R20, the i5-11600K almost catches up with Ryzen 5 5600X, and it easily dominates last year’s Comet Lake i5 equivalent. It doesn’t come very close to its Ryzen competitor in Passmark or Geekbench multithreaded tests, but it does outpace last year’s model all the way around.

This represents the clearest, most significant generation-on-generation victory we saw out of Rocket Lake-S.

Single-threaded CPU performance

Core i9-11900K manages to set new records for single-threaded performance—if by razor-thin margins, when compared to Ryzen 9. Compared to last year’s Comet Lake i9, those margins are much less thin.

As always, we advise readers not to make too much hay of this. Few real-world workloads are genuinely single-threaded, and even the largest margins shown here are quite thin.

Core i5-11600K gets within a hair’s breadth of Ryzen 5 5600X on single-threaded benchmarks, and it does so while scoring somewhat more significant victories over last year’s Core i5-10600K. For the most part, this is the same relationship we saw between Rocket Lake-S, Zen 3, and Comet Lake in the previous Core i9 versus Ryzen 9 slides.

Gaming performance

To our surprise, 3DMark gaming benchmark Time Spy disapproved of our Rocket Lake-S samples—and did so disproportionately to the results we saw from more general-purpose benchmarks Cinebench R20, Passmark, and Geekbench 5. Both Core i9-11900K and Core i5-11600K came in at hefty Time Spy disadvantages to their 2020 10th-generation equivalents.

Before you get too alarmed, this is the Time Spy CPU test only—it focuses on modeling physics in ways that don’t lend themselves to GPU rendering. Assuming that typical games would see similar decreases in overall frame rate would be a grave error. Time Spy Extreme—which allows more advanced processor optimizations and higher thread count—exposes an even wider gap. (We only tested Time Spy Extreme on the Core i9.)

As we noted in the gaming-focused Spring 2021 System Guide, the CPU has minimal impact on AAA gaming—frame rate in most games is determined almost entirely by GPU. If the only thing you have open on your PC is the game, you only need to meet a minimum CPU threshold—roughly speaking, “2015-era i5 or better.” However, the more extra tasks you load onto your system—browser tabs and email clients open in the background or, worst of all, stream-capturing your own games—the more CPU horsepower you’ll need to keep things moving.

We saw effectively no change in overall Time Spy score between 10th- and 11th-generation CPUs—and we didn’t expect to. Yes, the single-threaded performance increased significantly; no, that doesn’t generally have a large impact on gaming performance.

Integrated GPU performance

Rocket Lake-S gets an upgrade to its integrated graphics—but if you were hoping for UHD 750 to play in the same league as Iris Xe and Vega 11, you're out of luck.
Enlarge / Rocket Lake-S gets an upgrade to its integrated graphics—but if you were hoping for UHD 750 to play in the same league as Iris Xe and Vega 11, you’re out of luck.

Jim Salter

Rocket Lake-S gets a small but noticeable upgrade to its integrated graphics performance—the 10th-generation Core CPU’s UHD 630 graphics gets bumped up to UHD 750. While it is an improvement, it’s nothing to write home about—if you were hoping for an equivalent to Intel’s Iris Xe graphics in Tiger Lake laptop CPUs (or AMD’s Vega 11 in desktop APUs) you’ll be sorely disappointed.

A modest GeForce GTX 1060 is good for a Time Spy Graphics score of roughly 4,000. Intel’s flagship i7-1185G7 laptop CPU manages nearly half that at 1572, with AMD’s Vega 11 lagging noticeably behind at 1226. Rocket Lake-S’ UHD 750 comes in at a yawn-inducing 592—a little less than half the performance of Vega 11 and a little more than one-third the performance of Iris Xe.

Although the UHD graphics are sorely underwhelming, we should point out that they do at least exist. Competing Ryzen CPUs in the retail channel offer no integrated graphics at all—and with the current supply shortages and ugly price hikes in discrete GPUs, that can mean paying a nasty premium in full-system builds that aren’t supposed to focus on gaming in the first place.

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