A Moderate Refresh
Intel announced its Core i5-9400 processors in January, but the chips only recently become available in significant quantities. The company also rolled out the rest of its Coffee Lake refresh models, six months after its initial salvo, a delay likely attributable to its ongoing 14nm production shortage.
As Intel struggles to satisfy demand for its chips, AMD has launched its Ryzen 3000-series processors. The updated Ryzen line-up employs a smaller 7nm process that should confer power and price benefits. It'll also wield the new Zen 2 microarchitecture, which is expected to boost performance while Intel remains mired in a derivative of the seven-year-old Skylake design. These chips have now taken our Best CPUs list by storm, so be sure to head there for a list of the latest leading processors.
Intel's lingering lack of 14nm capacity reverberates through every facet of the industry. To boost supply, the chip-maker decided to start selling CPUs that it would have otherwise deemed defective due to nonfunctional graphics units. As a result, we now have the F-series, which includes disabled graphics hardware, but is otherwise identical to the fully-featured Core processors we're more accustomed to.
That means the Core i5-9400F is nearly identical to the Core i5-9400. Both CPUs serve to replace the impressive Core i5-8400, which was one of the most popular Coffee Lake models. Armed with 6C/6T and a slightly higher clock rate, the 9400s yield an incremental step forward over their predecessor.
Moreover, we're finally seeing the F-series' lower price kick in. The Core i5-9400F's ~$20 discount could be compelling for mid-range gamers who don't need integrated graphics.
Core i5-9400F and Core i5-9400
From an architectural standpoint, the Core i5-9400 and -9400F are essentially the same processor as the Core i5-8400, right down to their 14nm++ process, six physical cores, support for dual-channel DDR4-2666, and 65W TDP. The CPUs also drop into an LGA 1551 interface, and they are supported by existing 300-series motherboards with up-to-date BIOSes. They're multipler-locked, unfortunately, so they include Intel's flimsy stock cooling solution.
|Core i5-9400F||Core i5-9400||Core i5-8400|
|Architecture||Coffee Lake-R||Coffee Lake-R||Coffee Lake|
|Socket||LGA 1151||LGA 1151||LGA 1151|
|Cores / Threads||6 / 6||6 / 6||6 / 6|
|Base Frequency (GHz)||2.9||2.9||2.8 GHz|
|Boost Frequency (Active Cores - GHz)||4.1||4.1||4.0 GHz|
|PCIe Lanes||x16 Gen3||x16 Gen3||x16 Gen3|
|Integrated UHD Graphics GT2 (Base/Boost MHz)||350 / 1,050||No||350 / 1,050|
|Recommended Customer Pricing||$182||$182||$182 - $187|
Again, the Core i5-9400F lacks integrated graphics, which isn't an issue for gamers who already use add-in GPUs. However, we find it interesting that Intel maintains the same $182 recommended price as its standard Core i5-9400.
|Active Cores (GHz)||Base Frequency||1||2||4||6|
Relative to the Core 5-8400, Intel boosts the -9400/-9400F's base frequency and Turbo Boost clock rate by 100 MHz, which should yield slight performance benefits. The Core i5-9400 models also include new baked-in silicon mitigations for the Meltdown vulnerability, along with a combination of hardware- and software-based mitigations for the Spectre and L1TF vulnerabilities. The overhead of software-based patches applied to older processors can reach as high as 10% in certain workloads. That impact is greatly reduced on newer processors. Compared to the Core i5-8400, we didn't measure any significant speed-ups beyond what we expected. However, optimized mitigations could help deliver more of a performance uplift to enthusiasts migrating from much older platforms.
With the launch of its Coffee Lake refresh, Intel finally switched to a solder-based thermal interface material (sTIM), improving heat transfer between its die and heat spreader. Interestingly, though, some Core i5-9400 models initially came with standard polymer-based thermal interface material (thermal grease), while others shipped with the more efficient sTIM. Intel tells us that depended on where each CPU was manufactured, though all Core i5-9400s now come with sTIM, while the locked F-series models continue to employ pTIM.
In either case, you can determine whether your CPU includes sTIM by checking its stepping. P0- and R0-stepping processors come with sTIM, while the U0 and B0 steppings utilize pTIM. Intel plans to stick with pTIM for all locked F-series models, like our U0-stepping Core i5-9400F.
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