Intel Core i5-8400 Review: Six Cores On A Budget

Final Analysis

Intel's Core i5-8400 is the cheapest modern six-core CPU, if you believe the company's recommended customer price. That's quite the feat, given AMD's competitive Ryzen 5 family. Although the -8400 ships with the Coffee Lake line-up's lowest base clock rate, that frequency is offset by more aggressive Turbo Boost bins. As such, lightly-threaded apps spin up nicely, while parallelized workloads benefit from six physical cores working together.

Given Core i5-8400's pedigree, most of us are probably here to learn more about the chip's gaming alacrity. We plotted its performance using average frame rates and a geometric mean of the 99th percentile frame times (a good indicator of smoothness), which we convert into an FPS measurement.

Newer titles are often optimized to extract more performance from CPUs with more than four cores. Our suite includes six games released in 2016 and five older titles that launched in 2014/2015. So, curious whether the latest Intel and AMD many-core processors contribute affect frame rates in a positive way, we're including a chart that breaks out the newer games on their own.

CPUs below the $200 threshold are our key focus, and in its price class, Intel's Core i5-8400 provides the best gaming performance in spite of its locked multiplier. Even when we include a stock ~$215 Ryzen 5 1600, the Core i5-8400 holds its lead. It's only after shining a spotlight on the newer games using an overclocked 1600 that AMD carves out an advantage. Then again, processors in this price range are typically paired to mid-range graphics cards (rather than GeForce GTX 1080s), so you might not see much difference between the comparable AMD and Intel chips.

More important, Core i5-8400 wrecks the Core i5-7400. It's also faster than a stock Core i5-7600K. It can't quite match a Core i7-7700K, like the -8600K, but you're still getting a ton of value, given the similar price point as Core i5-7400.

Moving on to the application charts, Core i5-8400 distances itself from other processors in its price class, beating the previous-gen -7600K in threaded workloads as well. That's downright compelling progress from one generation to the next. Of course, stepping up ~$30 and overclocking a Ryzen 5 1600 should get you similar performance as a Ryzen 5 1600X. And in that case, you'll definitely outperform the Core i5 in heavily-threaded workloads. The compromise is lower performance in lightly-threaded apps and a higher price tag.

Intel's hasty launch means we're stuck pairing mainstream CPUs to higher-end Z370 motherboards until early next year. That's not a great option when you're dealing with a multiplier-locked CPU. Fortunately, the least-expensive Z370-based platforms sell for a reasonable $120. We're far less enthused about Coffee Lake supply issues causing prices on Core i5-8400 and other models to soar through the roof. Many retailers are selling the -8400 for $200 and higher. Hopefully, Intel can address this issue sooner than later. At least you get a bundled heat sink and fan as a consolation prize.

Overall, the Core i5-8400 offers incredible value to gamers on a budget, providing you can find the chip selling for Intel's recommended customer price. As supply stabilizes, you should be able to get your hands on an affordable hexa-core CPU that frees up funds for a faster graphics card than you would have purchased before. Balance is a beautiful thing to PC builders, and Coffee Lake delivers in spades.

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  • velocityg4
    I'd be interested in knowing. Under what circumstances can you get it to hit 3.8Ghz reliably under a 6-core load? That is quite a spread.

    If one was to delid the CPU and use a decent CPU cooler. Would it reliably maintain the max turbo boost when the CPU usage demands it? Is the stock heatsink and decent case cooling plenty?

    On another note. It is time for the return of the Turbo button. That would be pretty sweet to click the button and manually have the CPU jump between 1, 2, 4 and 6 cores at their respective boost frequencies or down to standard. I know it isn't necessary as it is all automated and that wasn't the purpose of the Turbo button. Some people just like manual control. Plus old time computer geeks would get a kick out of it.
  • AgentLozen
    This is a very neat chip at it's price point. Very little has changed between Kaby Lake and Coffee Lake except for the core count. Luckily for Intel, those added cores make all the difference.

    This CPU would sit nicely on a budget system. It's a shame that there are no inexpensive motherboards that it could fit into like the conclusion of this article states.

    If you didn't plan to overclock, this is the best CPU on the market for gaming and general productivity.
  • The_King
    We have AMD to thank for all these budget cpu's from Intel, and you all know why! So thank you AMD.
  • rwinches
    No, you can't have charts based on FPS or seconds or related to MSRP. Drivers update, Prices change, Memory Speeds Increase and price lowers, MB prices are wide range.

    It is known that Some games work better for AMD when AMD GPUs are used. Game FPS can be dramatically improved by changing just one parameter. Test results that are milliseconds or a few seconds or frames faster are irrelevant and subject to variations in real world use on systems that are not clean installs and have other SW installed and running.
  • 10tacle
    Anonymous said:
    No, you can't have charts based on FPS or seconds or related to MSRP. Drivers update, Prices change, Memory Speeds Increase and price lowers, MB prices are wide range.


    I don't understand your point. This is a review of the 8400 and comparing it to other CPUs only. Memory, motherboards, and all the other variables are you talking about in a full PC build are irrelevant to this chart comparison. They have to establish a constant standard across the spectrum, and they did so.

    Anonymous said:
    It is known that Some games work better for AMD when AMD GPUs are used. Game FPS can be dramatically improved by changing just one parameter. Test results that are milliseconds or a few seconds or frames faster are irrelevant and subject to variations in real world use on systems that are not clean installs and have other SW installed and running.


    Again, they are using a single standard across the spectrum comparison. Of course there are infinite combinations of hardware that can game change a little. The bottom line here is that among every major tech review website, all of Intel's chips are better for gaming than Ryzen. The only exception is when dealing with beyond 1080p gaming like QHD or UHD where it's mostly on the GPU. People who buy this chip are the perfect candidate for a 144Hz 1080p G-sync or Freesync monitor.
  • lotusmotors
    Glad I didn't waste money on a 1600x.
  • elbert
    Compared to the Ryzen 1600 with a B350 its $50 higher. That is a higher video card level. IE get the 8400 with a 1050ti the Ryzen budget would get a 1060 3GB. Intel needs their B360 motherboards for the 8100 and 8400 to ever be a budget winner.
  • hixbot
    Why did you label section 10, overclocking, cooling and temperature? There's no overlocking on this chip? I would have like to see at least an attempt at Bclk overlcock with a mobo that has a clock generator.
  • TJ Hooker
    I really wish more reviewers would look at what sort of boost clocks the i5 8400 can sustain under load, with the stock cooler as well as aftermarket. From what I know you could typically assume past Intel CPUs would operate at or near max turbo almost indefinitely, but with a 50% increase in core count and such an unusually wide gap between base and boost clocks (not unlike their mobile CPUs), I'm curious how Coffee Lake will behave in that regard.
  • ATI9800Pro
    There's a typo in the temperature charts ; it reads "Core i7-8400".
  • John__Titor
    Seems like a very solid CPU, but no way would I list the included cooler as a pro. It's cheap garbage. At the very best it's neutral. AMD has set a new standard for stock coolers that should be encouraged for budget processors.
  • PaulAlcorn
    Anonymous said:
    <snip>

    On another note. It is time for the return of the Turbo button. That would be pretty sweet to click the button and manually have the CPU jump between 1, 2, 4 and 6 cores at their respective boost frequencies or down to standard. I know it isn't necessary as it is all automated and that wasn't the purpose of the Turbo button. Some people just like manual control. Plus old time computer geeks would get a kick out of it.


    I second the vote for the return of the Turbo button. Good times!
  • PaulAlcorn
    Anonymous said:
    Why did you label section 10, overclocking, cooling and temperature? There's no overlocking on this chip? I would have like to see at least an attempt at Bclk overlcock with a mobo that has a clock generator.


    Good catch, fixed. Intel has been pretty good at locking out BCLK overclocking even on boards with an external clock generator. We'll keep an eye out for any further attempts at this, though.
  • Nintendork
    VELOCITYG4
    Why even bother having to delid a cpu and change tim to actually have a working cpu instead of simply buying the cpu king Ryzen 5 1600-1600X and forget about having to patch intel's mess?
  • HERETIC-1
    Hi Paul,
    When you mention-comes with a free cooler-would have been nice if you could
    have tested it-perhaps running Handbrake,and also then checked what turbo
    speeds it could maintain with stock cooler.
    As a budget 6 core I feel that is typical use,

    I feel for gaming-those that can't afford 8600K are likely to go for the cheaper
    4 core 8350K,which will probably be faster than 8400 in most games............
    If we get a non K 8600 next year-that could be interesting...........
  • Papatom
    I have looked at Tom's coverage of both Ryzen and Coffee Lake.
    From what I could see, there is a strong preference to show intel products in a better light.

    1. Pricing. THG chooses platform/processor alone costs as they see fit; any sane choice would include at least the cooling solution and, perhaps, motherboard into this. Not at THG though; I expect this to change when cheap intel mobos arrive.
    2. Cooling. You guys here seem to use good cooling (as in: expensive and performing), yet you do not inculde the costs into the equation. Combined with better thermals of competitive AMD offerings, this is smelly.
    3. Hand-picked benchmarks - blender and lux-what? included, POV-ray and Cinebench excluded. You guessed it, AMD hardware tends to have upper hand in the latter (excluded ones).
    4. Looking thru fingers at contest rules. RX 480 was over the TDP, you named and shamed it. i9s were over their respective TDPs, you failed to clearly state so.

    I no longer find this website serving just information for me to make educated purchasing decision.
    I am fed up. From a regular reader back in '90 thru early this decade, I decided to leave this site for good.
  • mapesdhs
    "... the 8400's multi-core Turbo Boost bins get a lot more aggressive than Core i5-7400's."

    Just curious, if the CPU can handle all six cores at 3.8 anyway, why is the base clock so much lower? Why not just set the base clock to 3.8 anyway? Or is it because it could only sustain 3.6 if the cooler was up to the task? If so, then Turbo has morphed into a sort of pseudo-Intel-sanctioned auto oc'ing.

    Also, since the 6-core turbo level starts off from a higher frequency, the percentage gain of the higher levels vs. the 6-core turbo level is lower than the inter-level gains for the old 4-core, which is if anything IMO somewhat less imppressive.

    Ian.
  • TJ Hooker
    Anonymous said:
    I have looked at Tom's coverage of both Ryzen and Coffee Lake.
    From what I could see, there is a strong preference to show intel products in a better light.

    1. Pricing. THG chooses platform/processor alone costs as they see fit; any sane choice would include at least the cooling solution and, perhaps, motherboard into this. Not at THG though; I expect this to change when cheap intel mobos arrive.
    2. Cooling. You guys here seem to use good cooling (as in: expensive and performing), yet you do not inculde the costs into the equation. Combined with better thermals of competitive AMD offerings, this is smelly.
    3. Hand-picked benchmarks - blender and lux-what? included, POV-ray and Cinebench excluded. You guessed it, AMD hardware tends to have upper hand in the latter (excluded ones).
    4. Looking thru fingers at contest rules. RX 480 was over the TDP, you named and shamed it. i9s were over their respective TDPs, you failed to clearly state so.

    I no longer find this website serving just information for me to make educated purchasing decision.
    I am fed up. From a regular reader back in '90 thru early this decade, I decided to leave this site for good.

    1. They addressed the fact that you'll need to pair the 8400 with a more expensive Z370 mobo for the time being in the first page, as well as in the conclusion.
    2. Ok this I kind of agree on. In the review they use a massive 420mm rad AIO cooler or a compressor cooler water loop, but then conclude that a basic air cooler is fine for cooling, and don't address stock cooler performance at all.
    3. AMD performs just fine in the benchmarks they did pick though. The 1600X outperforms the 8400 (and usually the 8600K) in both Luxrender and Blender.
    4. They called out the RX 480 for violating the PCIe spec on the max current/power that could be drawn from the motherboard slot (and even then they said this probably wouldn't be an issue 99% of the time, IIRC). That's not the same as going over TDP. TDP was never supposed to be an accurate measure of power consumption anyway. Apples to oranges.