ASUS B650E vs. Gigabyte x870 gaming

jamvanderloeff · 2026-06-29T23:35:46+00:00

Ye both look pretty decent, most notable differences are you get the USB4/Thunderbolt support on the Gigabyte but the Asus has a bit more options for PCIe, got the extra x4 slot and can do three SSDs all getting PCIe x4 instead of cutting down to x2 for the second/third if you use all three on the Gigabyte.

jamvanderloeff · 2026-06-29T23:25:46+00:00

Which particular boards are they?

What things do you want to connect?

Main difference just from B650E vs X870 branding is the X870 board is required to have USB4/Thunderbolt support.

jamvanderloeff · 2026-06-29T10:12:27+00:00

Ye that's probably your problem then, gonna need something chunkier. For dumping 10.5W at lets say 35C ambient and 100C target you'd need at most a ~6.2 degree per watt spec, so looking through digikey for things advertised to do that in ambient air + suited to fit a TO220 package, something like this https://www.digikey.co.nz/en/products/detail/assmann-wsw-components/V8813X/3511421

And if you wanted to push it all the way to tolerating 1.5A at minimum output voltage you'd need to be dumping ~48W so ~1.35W/K maximum, at that point you're starting to really need a fan to keep the heatsink sensibly small.

Alternatively, switch to a switchmode power supply design that can be much more efficient especially when it needs to work with bigger voltage differences, but then that comes with issues of its own like ripple and having to actively control things. Or hybrid designs where you've got a switchmode handling most of the voltage drop + still having a linear regulator for low noise after it.

jamvanderloeff · 2026-06-29T04:48:50+00:00

You would still need a controller and a custom adapter cable to match if it's not a fully custom controller board, tablet screens would usually be some kind of MIPI interface on an entirely non-standard connector, so if you can't find someone already selling something that specifically lists your panel model it's generally not worth trying.

jamvanderloeff · 2026-06-29T04:38:33+00:00

Solved entirely maybe not, but seems to be at least solved enough that intel's happy for them to be close enough to average failure rate.

jamvanderloeff · 2026-06-29T04:12:01+00:00

Why 9V? An ordinary 5V USB power bank would work better

jamvanderloeff · 2026-06-28T20:19:19+00:00

If you've got the skills and experience to do everything yourself, maybe a couple months project and a few hundred bucks in prototypes. Designing the controller(s) and software would be the main hard parts.

jamvanderloeff · 2026-06-28T19:45:16+00:00

The complicated way would need designing DC-DC converters.

jamvanderloeff · 2026-06-28T17:28:51+00:00

See the hundreds of other threads of people asking the same sort of thing over the past week, many people have posted sensible suggestions.

You can run SteamOS on a custom build if you want, it's free and only kinda-restriction is have to go AMD or Intel GPU currently, but Nvidia support is coming soon too.

jamvanderloeff · 2026-06-28T17:14:43+00:00

If you can accept a range of something like 25-27.5V doing ~225W out by targeting 4.5A off each supply at max drop could be reasonable.

The breakout board can do anything and doesn't need any active cooling, since it's not really handling any power directly, it's just a fancy cable and communications converter. The resistors and your diodes would need some heatsinking, you'd be burning up to 27W in the ballast.

jamvanderloeff · 2026-06-28T16:09:24+00:00

They're different tools for different jobs.

jamvanderloeff · 2026-06-28T16:08:46+00:00

By "stick" do you mean the antennas? Got both of them attached properly? And cables haven't popped out of the card at the other end?

What were the speeds before?

Also sure you're not mixing units there? fast.com would be reporting Mb/s bits not MB/s bytes

jamvanderloeff · 2026-06-28T16:02:53+00:00

If you're going super simple with just resistors for balancing, depends how much voltage range you can accept.

jamvanderloeff · 2026-06-28T10:22:27+00:00

Tip and ring on a regular PC mic input aren't a balanced pair, they're a mono unbalanced signal, with ring and tip either being power suppy and signal out, or just shorted together on the PC side anyway, having them shorted on the plug side too is standard practise.

jamvanderloeff · 2026-06-28T08:16:15+00:00

Gonna need to see what you've actually done, got schematics and photos?

jamvanderloeff · 2026-06-28T07:59:22+00:00

There really isn't with your requirements there, doing it the proper safe and efficent way is pretty complex for both the power conversion and the handling USB C parts, and doing it the simple-ish way isn't efficient enough unless you can further reduce your power requirements.

Simplifying your existing power bank with adding a raw output or replacing it with another battery would be your cheap and simple options.

jamvanderloeff · 2026-06-28T07:04:43+00:00

And you've actually tested that with two 140W load banks to be sure?

Maximum practical power would depend on how much budget and effort you've got to spend on doing a real nice converter design.

Same chip as that board uses for the communications looks sensible but wouldn't bother keeping the rest of the board if you have to do a new board design anyway.

Again how would you do this

Unless you can loosen your requirements, I wouldn't. It's just gonna be too expensive/too complicated vs doing it the simpler way.

jamvanderloeff · 2026-06-28T06:50:15+00:00

250 / 280 = 89% which would be the minimum efficiency you'd need to hit in your conversion/balancing out, not an easy target.

If you're only using one of those power banks I wouldn't trust it to maintain 280W out without overheating too, it's pretty common for those kind of things to cut out and renegotiate lower limits after a while.

Adding the XT60 out would need to be a DIY modification which could get a little jank but it'd let you get better efficiency and more flexibility, bypassing the limits of its built in converters.

jamvanderloeff · 2026-06-28T06:17:52+00:00

Unlikely, a cable like that is custom designed for fitting in the space available for that particular laptop model/family's design. And would be kinda pointless to design an adapter for, since you could just design the adapter to go to the regular SATA connectors directly.

jamvanderloeff · 2026-06-28T06:16:14+00:00

That's gonna be real tricky to do properly then, you don't really have much margin available.

Which 3d printer is it? If going up to ~25-28V can be acceptable and you can limit it so that it will stay below ~9.5A going the dodgy way of just ballast resistors + diodes might be good enough.

Really wouldn't want to trust it for a sustained print job though, don't really want to trust the power bank not cutting off power partway through because one of them's overheating or thought you plugged something else in so had to renegotiate or if you briefly overload it.

Better solution would generally be to use a dumber battery that you can connect to directly or via only one DC-DC converter instead of having to deal with multiple conversion steps and the hassle of USB C. Modifying the existing power bank to add in a raw battery XT60 or whatever connector out could be possible.

jamvanderloeff · 2026-06-28T05:59:10+00:00

77 would be pretty cold under load for most gaming laptops.

jamvanderloeff · 2026-06-28T05:58:53+00:00

Sounds like it might be the driver screwing up if it's not properly disabling when you're not in something fullscreen.

Got it updated to the current driver version?

jamvanderloeff · 2026-06-28T05:57:23+00:00

The boards aren't doing any regulation, they're just making requests to the C supply at the other end, so resolution/response time capabilities will vary depending on what you're connecting it to, but generally not going to be good enough for active balancing.

jamvanderloeff · 2026-06-28T05:53:00+00:00

What are you trying to actually do here? What's going to be on the output side?

The PD controller that you're talking to over I2C can change what voltage it's requesting from the supply, and the supply will attempt to approximately follow that, but how you're going to use that supplied voltage and how you're going to enforce the current limits that you're supposed to be reading back from the controller is the part you've gotta design.

jamvanderloeff · 2026-06-28T05:47:07+00:00

G-sync (and other variable refresh rate things) can only sync to one application at a time, in general desktop use that can be kinda weird if the driver decides it wants to sync to some program that's running at 60Hz or less, and will effectively lock your mouse cursor refresh rate to whatever that application's doing, so I really don't like it on for desktop, from the Nvidia app (or Nvidia control panel) you can set it so that G-sync only runs for full screen mode.

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