Question Recommended motheroard for a 285K CPU ?

[Regev]

I'm trying to build a computer around an Intel Core Ultra 9 285K CPU (got it for a heavy discount, otherwise wouldn't get it at all). It's going to sit on my desk, so it shouldn't be too tall or big in general. I haven't had an ATX board for 15-20 years, have since moved to SFF computers with MinITX mostly (sometimes micro ATX, as some nice cases allow that). However, I see mostly massive ATX cases around., at least with the z890 chipset

My question - beyond overclocking (which I understand isn't as big as it used to be when i started building computers in 2004), are there major differences in VRM and component quality in general? I've always bought Z series boards... and intentionally never overclocked. I bought them because I assumed they're meant for overclock, so they're built better with higher voltage durability. So it felt reassuring to have them, just as an insurance policy against failure.

How are the B860 boards these days compared to the Z890 ones?
I'd like a mATX or a MiniITX board if possible - but I don't want to skimp on the quality, and I certainly don't want to spend $300 or more.

I saw this crazy comparision this guy did here:

https://www.techspot.com/review/2949-intel-z890-motherboards/

I noticed all mATX z890 boards have Failed POST his memory stress test: (and I intended to use the fastest CUDIMM sticks I could get my hands on, if they're reasonably priced)

Memory validation took a long time due to the sheer number of boards – 50 in total – and we conducted only a one-hour stress test per board. All boards passed Gear 2 validation at 8200 MT/s and 8400 MT/s, but 8800 MT/s proved to be more challenging. Only 15 boards successfully passed the hour-long stress test, while 19 failed to POST. The remaining boards either crashed when loading into Windows or failed during stress testing.

Anyway, any recommendation for a mATX or a Mini ITX board with solid VRM stability, temps, and build quality, that won't cost above $300 ?

 

[emily1221]

Totally get where you're coming from — you're not alone in wanting a compact, clean build around that Ultra 9 285K without the bulk of ATX.
Here's the deal, short and sweet:

• Z890 vs B860: Z890 boards are built for overclocking, so yeah, generally better VRMs, more features, and more robust components. But if you're not overclocking, you're paying for stuff you won't use.
• B860 today: Surprisingly decent. Some have solid VRMs and will easily handle a 285K at stock speeds — just do a little model research. You're mainly giving up PCIe lanes and RAID, not quality or stability.
• mATX/ITX options: They're few and often compromise on VRMs due to size. You’re right about that TechSpot review — some of those smaller Z890 boards did fail under memory stress with fast CUDIMMs.
• If you're chasing high-speed CUDIMM stability, you might be safer with a full ATX Z890 board. But if size matters more and you're okay with dialing down memory speed a touch, B860 mATX could still be a win.

 

[Regev]

Or I could just buy 8200 or 8400 How much performance am I giving up compared to 8800?

ll boards passed Gear 2 validation at 8200 MT/s and 8400 MT/s, but 8800 MT/s proved to be more challenging.

There's going to be a 9070XT and probably a Gen 4 or 5 - 2TB Nvme.

I'm seeing this comparision, so i think it'll be enough:

Chipset PCIe Lanes (4.0)
Z890	5.0 x16* (GPU) 5.0 x4 (M.2) 4.0 x4	24	Yes	14	5×20 Gbps; 10×10 Gbps; 10×5 Gbps	8	IA, BCLK, RAM
B860	5.0 x16 (GPU) 5.0 x4 (M.2)	14	Yes	12	2×20 Gbps; 4×10 Gbps; 6×5 Gbps	4	RAM

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Chipset​

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CPU PCIe Lanes​

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Thunderbolt 4​

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USB 2.0​

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USB 3.2
(Choose one)​

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SATA Ports​

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Overclocking​

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Any b860 out there with internals as high-quality and durable as the best z890 equivalent?

 

[dwd999]

If you're concerned about case size with an ATX motherboard the 2 smallest cases I've used are the Silverstone Grandia GD11 (horizontal) and the Lian Li O11 Air Mini (vertical). The GD11 will hold a Noctua NH-D12L cooler and the Air Mini will hold an NH-D15 G2 cooler or a 240 AIO. You haven't specified how large is too large but you might check those out before limiting yourself to an mATX or ITX.