Why you can trust Tom's Hardware Our expert reviewers spend hours testing and comparing products and services so you can choose the best for you. Find out more about how we test.
Our standard benchmarks and power tests are performed using the CPU’s stock frequencies (including any default boost/turbo) with all power-saving features enabled. We set optimized defaults in the BIOS and the memory by enabling the XMP profile. For this baseline testing, the Windows power scheme is set to Balanced (default) so the PC idles appropriately.
Synthetic Benchmarks
Synthetics provide a great way to determine how a board runs, as identical settings should produce similar performance results. Turbo boost wattage and advanced memory timings are places where motherboard makers can still optimize for stability or performance, though, and those settings can impact some testing.
The board did well across our synthetic applications, with average to above-average results in all these tests. There is nothing abnormal to report.
Timed Applications
While the results in the timed benchmarks are all tightly packed, the B850I Lightning WiFi continued to do well and lead most other results. It was first in LAME, and both Handbrake tests were mixed in with the other boards in Corona—another good showing.
3D Games and 3DMark
Starting with the launch of Zen 5, we’ve updated our game tests. We’re keeping the F1 racing game but have upgraded to F1 24. We also dropped Far Cry 6 in favor of an even more popular and good-looking game in Cyberpunk 2077. We run both games at 1920x1080 resolution using the Ultra preset (details listed above). Cyberpunk 2077 uses DLSS, while we left F1 24 to native resolution scaling. The goal with these settings is to determine if there are differences in performance at the most commonly used (and CPU/system bound) resolution with settings most people use or strive for (Ultra). We expect the difference between boards in these tests to be minor, with most falling within the margin of error differences. We’ve also added a minimum FPS value, which can affect your gameplay and immersion experience.
The board was in the middle of the pack for the 3DMark benchmarks, but for games was at the top. It was just as performant here as it was in the synthetic and productivity testing—an all-around performer.
Overclocking
Over the past few CPU generations, overclocking headroom has been shrinking on both sides of the fence while the out-of-box potential has increased. For overclockers, this means there’s less fun to have. For the average consumer, you’re getting the most out of the processor without manual tweaking. Today’s motherboards are more robust than ever, and they easily support power-hungry flagship-class processors, so we know the hardware can handle them.
There are multiple ways to extract even more performance from these processors: enabling a canned PBO setting, manually tweaking the PBO settings, or just going for an all-core overclock. Results will vary and depend on the cooling. In other words, your mileage may vary. Considering all of the above, we’re not overclocking the CPU. However, we will try out our different memory kits to ensure they meet the specifications.
As you may have read earlier, we could run all kits except the DDR5-8000 without issue. If you follow the memory QVL list (we didn’t), you’ll have a better chance of reaching these higher speeds.
Power Consumption / VRM Temperatures
We used AIDA64’s System Stability Test with Stress CPU, FPU, Cache, and Memory enabled for power testing, using the processor's peak power consumption value. The wattage reading is from the wall via a Kill-A-Watt meter to capture the entire PC (minus the monitor). The only variable that changes is the motherboard; all other parts remain the same. Please note that we moved to using only the stock power use/VRM temperature charts, as this section aims to ensure the power delivery can handle flagship-class processors.
The Ryzen 9 9990X's power consumption is tame compared to the 7950X we used for X670/X670E. Where, in the past, high-end boards would peak at nearly 300W, the systems now top out at 250-270W during the CPU stress tests (gaming with the Nvidia RTX 4080 is another story). The B850I Lightning peaked at 263W and idled at 72W, one of the lower idle values. So long as you can keep adequate ventilation in your chassis, this board will support anything you can throw at it.
VRM temperatures peaked around 54 degrees Celsius in our testing. But mind you, that’s on an open-air test bench. Although they’ll run warmer in a case, there’s still plenty of headroom left.
Bottom Line
ASRock’s B850I Lightning is an excellent value in the Mini-ITX space. For just over $200, you get full support for AM5-based processors, including the higher-powered flagship-class options. You get capable power delivery, integrated Wi-Fi 6E, PCIe 5.0-capable M.2 and GPU slot, a solid audio solution, outstanding performance, and a generally neutral design sporting a black PCB and the Phantom Gaming purple and highlights, fitting most build themes. Performance was also good out of the box. Quite frankly, there’s not much to complain about here, especially when considering the price.
Regarding the competition, Asus’ B850-I Gaming offers Wi-Fi 7, faster USB (20 Gbps port), and a better audio codec, but it costs almost $100 more. Gigabyte’s B850I Aorus Pro has similar specifications as the Asus and can be found for $259.99), while MSI doesn’t have any skin in the B850 Mini-ITX game (they’re all ATX boards).
All options their pros and cons, but it will come down to budget and whether you need to spend the additional $50-90 on faster Wi-Fi and USB ports and a better (on paper) audio solution. If you don’t need those features, buying ASRock’s B850I Lighting for your modern, small-form-factor needs is a no-brainer.
MORE: Best Motherboards
MORE: How To Choose A Motherboard
MORE: All Motherboard Content
