These days the M.2 features and options are both major selling features for any mainstream (let alone enthusiast) motherboard. In this regards… the Carbon X870E is decent. Not perfect. Not great. But certainly decent. Before we begin, we feel the need to go over the chipset first… as it is controversial and its limitations do flow upstream to the M.2 section offerings. To be blunt, most of the problems we have with things here has to do with the fact that AMD did not upgrade the total lanes nor the bus generation or pretty much anything else when they recycled the dual P21 configuration for the ‘enthusiast’ X870E (dual) chipset… and make no mistake the X870E is basically just a (firmware) “refined” variant of the X680E (and its dual P21 chips).
On the positive side, at least the X870E is a top end chipset whereas the non-E 870 variant is just a refined version of the B650E… not the non-E X670. Oooof. On the truly positive side, the X870E (and non-E) now have USB 4 as a mandatory included feature, not as a nice to have but only as a high end optional feature like it was last gen. The downside to making USB 4 / 40G mandatory, while at the same time not increasing the number of (what AMD calls general purpose lanes “GPP”) from 12 PCIe 4.0 and eight PCIe 3.0, is all that USB high bandwidth goodness has to come from somewhere. So yeah, ‘bifurcation’ is the word of the day when it comes to nearly all X870E based motherboards which are forced to make similar compromises.
Yes, that “bifurcation”. That four-letter word with a lot more than four letters in it. The bane of mainstream buyers… and one of the biggest reasons to opt for ThreadRipper (if AMD ever gets around to refreshing it that is). What this is and does is simple. It cuts up the few PCIe lanes AMD offers in such a way to as allow buyers to use as much of them at the same time as they can. Every motherboard design team will prioritize things definitely, but one thing remains constant: TANSTAAFL is always in full effect. There Ain’t No Such Thing As A Free Lunch.
So let’s break it on down. The lane sharing configuration on the X870E Carbon is rather interesting to say the least. To begin PCI_E1 (aka top most PCIe 5.0) slot, the PCI_E2 (‘middle’ PCIe 5.0 ) slot & M.2_2(aka second PCIe 5.0 slot directly below the top most M.2 slot) share the same 24 bandwidth lanes. Which is pretty logical and typical by X870E standards. However, it gets… quirky fairly quickly once you dig into how the bifurcation works on this motherboard. It gets quirky in that while the CPU offers 20 lanes of PCIe 5.0 goodness you not actually going to get access to them all, all the time… only some of the time.
First and foremost if you want sixteen lanes of bus width for your GPU, you cannot use the second / middle PCIe x16 slot nor can you use the M.2_2. Yes, stick even a PCIe 3.0 x1 Add in Card in that ‘x16 slot’ and it and the top goes right to x8 mode. Leave that middle slot empty but stick even an ancient PCIe 3 x2 M.2 in that fancy high test M.2 slot… and your GPU gets 8 lanes. Thus nuking four PCIe 5.0 lanes right out of existence. The only way to get all 16 at the same time is to either opt for populating just one, or for all to be populated. Put another way this motherboard takes both “E Pluribus Unum” (Out of many, one) and “Ex Uno Pluria” (Out of one, many) way too literally.
As such, if you do plan on using only 2 or even 3 M.2 drives… skip buying a second expensive PCIe 5.0 x4 M.2 and just get a PCIe 4.0 x4 one instead. If all those limitations sound like a dealbreaker… ooof. We got some bad news for you. Ripping that band-aid right off, the ASUS RoG Hero… that $699 USD, nearly 1K Canuckbucks motherboard… is worse. On that ‘PC Gaming” motherboard four ports all share bandwidth. To be specific, both x16 slots (PCI_E1 and PCI_E2) and two M.2 slots (M.2_2 and M.2_3) all share bandwidth… and the give and take equation makes the Carbon look like Algebra versus Calculus. With the only upside being that if you sacrifice two M.2 ports to the Gods of Gaming you can have both PCIe slots run in x8 mode. Slide one M.2 into the equation and its 8+4+4+0. Use both M.2s and the second X16 slot gets nuked… and its 8+0+4+4. Not fun. Not as straight forward. Not as flexible given the fact that the Carbon still has that ‘third’ PCIe (4.0 x4) slot and this costly board does not.
The Hero (aka $599 USD) does a three-way share/split between the second PCIe 5.0 x16 slot and two M.2 ports… but at least you can use all three at the same time. The ProArt Creator also does something similar with its second PCIe 5.0 sharing bandwidth with the M.2_2 slot. Thus both allow for 16/0/0, 8/8, and 8/4/4 bifurcation… and in turn always giving you access to all the ports/slots and PCIe lanes available. Thus the MSI MPG Carbon is quirky… but not ‘that’ quirky.
On its own that level of quirkiness would be far, far above average. After all, on paper all the above compromises sound logical. Even with a mighty Might Green Giant card (RTX 4090) x8 mode vs. x16 mode differences are minor, and yet being able to use a secondary PCIe 5.0 x8 Add In Card and a second PCIe 5.0 M.2 sounds like a decent tradeoff.
The reality is not so rosy. While MSI has indeed separated the PCIE “x16” slots by 3 full PCIe slots… by modern standards a 3-slot wide GPU is on the thin side these days. They would have been much better off swapping the second PCIe 5.0 x4 and PCIe 4.0 x4 (also in x16 form-factor) locations… and skipping the idea of two PCIe 5.0 M.2s. Instead making the M.2_2 a PCIe 4.0 x4 that shared not with the primary “CPU” lanes, but with the X870 Chipset’s PCIe 4.0 lanes. That way this board could do what few are doing this gen: offer a non-sharing main GPU slot and four M.2 ports.
As it stands this is a good layout, with clearly defined pros and cons. It’s just that for many, the MSI Carbon X870E will not stand out all that much. In either case, MSI does give buyers four M.2 ports (just like the ProArt Creator), not five (in a three gen 5 + 2 gen four configuration like it should, and like the STRIX-E and Hero both offer). So some (like ourselves) will be looking to add in an additional card or two via the PCIe slots to help boost the M.2 numbers up.
Also just like how most do it, the four M.2 ports breakdown into two PCIe 5.0 and two PCIe 4.0 ports. Interestingly, none are SATA reverse compatible… but at least the top most PCIe 5.0 slot is not the lone 110mm long compatible one! Instead it is the third M.2 (aka first PCIe 4.0 x4) slot that can handle 60 to 110mm long M.2 drives. Sadly, none are M2 2232 nor even M2 2240 compatible. Instead the smallest these ports can natively support is 22x60mm. Thankfully 32/40 to 60/80 adapters are cheap, and few will ever care about if say a Crucial P310 or Corsair MP600 Mini will fit.
So with the downsides taken care of, overall we do feel that MSI has done yeoman worthy work with what the X870E offers. They have given buyers a lot of flexibility, a lot of performance, and a lot of ease of use enhancements. Features like all four M.2 ports get the dual-sided heatsink based “M.2 Shield Frozr Technology” (that combines a lot of alloy with a lot of good heat pads to keep M.2 temperatures in check). All four get some variant of MSI’s “EZ M.2 Clip” tech that sets the standard for others on how to make an easy but secure M.2 installation.
Interestingly enough the top most M.2 Gen 5 does not get the new wiggly jiggle “v2” locking mechanism. Instead it uses the last gen EZ M.2 Clip 1.0… Which is superior in some ways and inferior in others. It is superior because the securing mechanism is larger, and a larger surface area means a more secure lock up. The downside is this swinging latch style mechanism does not play nice with all aftermarket M.2 cooling solutions (especially some ThermalRight models). Basically the beefiest aftermarket M.2 cooling solutions have more metal and heatpipes than MSI’s EZ Latch design team took into account when dreaming up this ingenious latch… and this extra beef can cause headaches when it comes to trying to fully swing the plastic latch closed.
This would be a non-issue, especially considering the new ASUS “Q-Slide” (and its plastic slider latch mechanism) is a major PITA, except MSI has once again opted for low profile M.2 heat sink. Compared to most, including the ProArt Creator WiFi, the top most ~3oz heatsink is decent but not outstanding by 2024 standards. In fact, with its built in Carbon LED logo it is fan-frickin-tastic considering the price range of the Carbon. However, compared to what STRIX X870E-E offers it is showing its age. Not only has ASUS rearranged the M.2 slots so that not one, not two, but three are above the GPU x16 slot…. but the top most gets a normal heat pipe based heatsink, the rear most gets a big boi heatsink (with integrated horizontal cooling fins) and even the 3rd is beefier than what MSI is not using. Arguably, this is as it should be as the STRIX-E is a much more expensive motherboard… but MSI’s design is starting to show some wear and tear, and needs an update.
This not so graceful aging is more than just skin deep and Asus is not only better at cooling but easier to work with when inside a case. To be blunt the Asus options (including the similarly priced ProArt) are better as they have moved to a front of the board unlocking mechanism versus the older back of the board unlocking that MSI is using. While it may not sound like much of a difference… it is when the motherboard is installed in some cases and big boi air coolers are used. In these scenarios not having to grab a long screwdriver to hit a ‘hidden’ latch so as to avoid having to yank the GPU just for a M.2 drive replacement is a big deal.
On the positive side, all four M.2s on the Carbon are now covered by screw-less EZ removal mechanisms and the posts are now on the motherboard and not the heatsink. So all one has to do is push in the metal button and then gently lift up to remove the 3-way (6oz) heatsink or the button for the single M.2 (3oz) heatsink. To reinstall, simply line up the big posts on the bottom of the 3-way, or the small on top of the top most m.2, slide the sink in to place and then push down. When you here the click… its secure.
Overall we like this section of the motherboard and think that a good 95 percent of buyers will more than happy with it… they will be ecstatic. It is just the last five percent who will want even more so as to avoid the ‘Asus Tax’.
Moving on to SATA.
Sigh.
For those who are actual storage enthusiasts the dropping from six on the last gen X670E Carbon to the four on its replacement stings. We understand the reasoning behind only using two blocks of dual SATA headers. We even agree that giving up 2 SATA ports to gain the extra dual USB 3.0 front header is a good deal. We just dislike the trend the industry is going. Unlike what some industry wonks keep chanting, SATA is not dead. Hard Disk Drives and their mega sized, yet extremely cheap, capacity will keep SATA going strong for years to come. So while the Carbon X870E is no different than the ProArt/Strix/Hero that is not a good thing. After all AsRock figured out how to include 6, so MSI should be able to as well.
Furthermore, what rubs salt directly into the wound is the fact that all of the M.2 slots lack SATA compatibility. Meaning the only way to boost the SATA ports up from four is via an Add In Card. Which means either unreliable, finicky, ‘SATA PCIe Expansion Cards” or expensive LSI HBAs… neither of which are optimal if you planned on using an AMD APU and the Carbon as the foundation for one primo living-room HTPC build.
Moving on before we need to break out the antacids. Running along the bottom edge of the motherboard is your typical assortment of headers (as well as the Power/Reset buttons we already went over earlier in the review). Three 4-pin fan headers. Two USB 2.0 headers (for a total of four USB 2.0 ‘case’ ports). Audio front header. Various other odds ‘n’ sods including the critical front header connectivity cluster…. Which once again has been given the “EZ Front Panel Cable” treatment. This cable makes it so you can plug in all your cases cables to this adapter and then simply plug it to the motherboard.
For those who have never used it before, we cannot stress how big a deal this is. It alone makes MSI Carbon X870E more user-friendly than even the RoG Hero. Tight case? No problem! Big case but short cables? No problem! Good case… but its pitch black down in the corner? No problem! This cable takes all the hassle out of this critical final build step.
Furthermore, MSI has also broken the front fan header section into two separate and distinct clusters… that are not even remotely close to one another. Specifically the Power, Reset, HDD, and Power LED headers (AKA JFP1) are in their usual bottom right corner location… but the 4 pins for the speaker are not. They are in and up from JFP1 (basically in line with the bottom most ‘PCIe 16’ / “PCIe 4.0 x4 but x16 looking slot”) and it is labeled JFP2 in the manual. Once again. A small tweak, but one that makes things easier.
Also located in this zone is a feature that many will love: the LED on/off switch! Yes. With just a flick of your fingernail you can turn all the LEDS off and create a truly ‘blacked out build’. Yes. We are biased, but we do love having this nifty feature included… as relying upon software to disable all the LEDs is a bit a PITA.
Moving on. We come to come to a feature that few others offer: the 8-pin “Supplemental PCIE Power” header. When we say special we do mean special, as ASUS does not include it on the ProArt nor the STRIX-E. Instead of the big 3 for ASUS we are comparing and contrasting against only the high priced Hero gets this feature.
So…what does it do? What it does is it increase the total 12v board power from the default 14A / 168Watts (if you exclude the EPS… which MSI wants you do to) to a whopping 35A/420 watts of 12v flavored go-go juice. Thus allowing the Carbon X870E to have enough 12v power to actually provide 75 watts to each of the PCIe slots. At. The. Same. Time. Without. Robbing. From. The. EPS. Headers. It can also be used to power RGB LED strips… fans… and everything else a growing list of accessory needs. Like we said, it is a special feature that few other companies are offering on all but their high-end motherboards.
With that said, MSI has not done as good a job as ASUS. With ASUS they stick it right next to the 24-pin motherboard power header. With MSI? It is down below the last PCIe slots. In and of itself this is not a big deal. What is… is MSI is not respecting the PCIe slot’s restricted z-height “no go” zone. So much so even a standard length x16 1slot card will not fit if you use that extra header! Furthermore it is self-inflicted error that need not have happened. All they had to do was move it past the PCIe slot’s latch… and swap the USB 2.0 and JRGB header’s location for it. Presto-changeo it’s a go-go. Still not optimal as ‘long’ 16x-slot cards would still not work with it… but better than being limited to such an extreme. Ooof. PCI-SIG is not gonna be happy with MSI when the complaints start to roll in as this is a rookie mistake.
On the positive side it will not impact the usage of standard PCIe x1 or even (most) PCie x4 length cards. Its only cards that sit further than the halfway mark that will block it. Also… this is an extra feature. One that is not needed, but not using it when its right there would be less than optimal to say the least. Hopefully one of the “Gray Beards” at MSI remember the days of yore when third 8-pins came on certain “SLI Gaming” motherboards… and dust off the policy and procedures on where to place it on the motherboard. If that is not possible (as it has been many a moon since we have seen this 3rd 8-pin on a mainstream motherboard)… take a hint from ASUS and put it up by the other power connectors. Hell, while ‘you’ are moving the two other 8-pin headers… move it too and have a row of three… just give this one a different color so as to make sure Bubba doesn’t figure out a way to jam a differently keyed CPU 8-pin cabled into it (as it is only pins 4 and 6 that are keyed differently between an 8pin PCIe and an 4+4 EPS cable/header combo)… or…you know… make it a ‘CPU’ / EPS-12v 8-pin so that all three are the same. Which as an added bonus would not only increase its power limit from 21A/252 watts to 300 watts but also make it a legitimate 300 watts versus the ‘official’ PCI-SIG 150 watts 8-pin PCIe limit it is supposed to adhere to… and yes PCI-SIG is salty over everyone ignoring that standard. Salty enough that it did play a role in why they backed NVIDIA and their “we don’t believe in an 20% safety margin” 12VHWPR standard.
This brings us to the integrated sound card. Which when we look at it the word “Spartan” does spring to mind. Yes. It is electronically separated. Yes… the big old hunk of metal over a good chunk of the area is technically an EMI shield (just not a very good one). Yes. Not much has changed from the previous gen except the fact that the number of ChemiCon caps is now just three.
Thus, it still is a ALC4080 (not 4082) based design. Some will like the fact that it (unlike with the ProArt) uses the more modern (circa 2022) RealTek IC instead of the older (2017) ALC1220. Others will be the opposite. Basically we are neutral on this debate. Neither are great. Neither are terrible. To us it is the implementation that matters more than the Codec itself. After all, the ALC1220 and ALC4080 are very similar in capabilities and basically just the connection to the CPU that differs from one to the other. The ALC1220 (used in the ProArt) uses traditional method (e.g. HD-A, I2S, I2C), whereas the 4000-series uses an integrated USB 2.0 controller and thus a USB bus to connect to the CPU.
Some will argue that the 4000 series suffers more from ‘noise’ than the 1220 it supersedes in Realtek’s product stack… as USB is typically a busy bus and thus can be noisy. But then again 1220s also randomly suffer from noise and it has more to do with the PSU quality (i.e. how much ripple) and how good the GPU is at suppressing ripple than either being ‘better’. So to us it simply is a “Ford” vs “Chevy” type deal. One where your past experience that will color your opinion one way or the other more than anything else. To be blunt, those who really care already have AIC soundcard to bypass it.
Considering the ProArt uses the older, the STRIX-E is like the Carbon and use ALC4080, and only the noticeably more expensive Hero uses the newer ALC4082… we are not alone in our assessment of it not really mattering all that much. They all get the job done to levels that used to require a PCIe based sound solution.
With that said, there are difference in the “headphone” opamp each board uses. Yes, and unlike the ProArt, MSI does include one. Yes the ~7.50 USD Analog Devices AD712 opamp is pretty decent. It just is not as good as the Savitech SV3H712 AMP the STRIX-E uses.. it that opamp is not even in the same league as the ES ES9219 the Hero uses. Which is fair given the large disparity in prices between the Carbon and those two boards (and ooof, the ProArt meant for ‘Content Creators’ does not live up to its name in the audio department!). Overall, the onboard sound option is decent, but certainly… spartan. Good enough to get the job done, but MSI certainly rounded a corner or twelve here in this corner of the board. We just doubt many will care enough to spend the added big bucks to fix it at the board level and not the 3rd party (AIC or USB DAC) level.
Before concluding our closer look of this section of the motherboard we do have to point out one last nifty feature of the X870E Carbon. The “button” battery location. In many Carbon’s (and others for that matter) the battery is located underneath the main heatsink. Meaning you have to tear down the board just to swap out a bad battery. With the Carbon X870E that is a thing of the past as they (finally) re-located it to near the PCIe slots. Once again, a little tweak that will be important to those with experience… but not even be noticed by those without. With that said, we must admit that ASUS may be on to something with putting it closer to the front of the board. We say this as in smaller cases the location MSI has chosen will be a smidgen harder to reach than the bottom front corner(ish) of the board. Certainly not a big enough deal to choose one motherboard over another, but something to add one side of the triple-beam before you make a final decision.
