Need Computer Engineer

I have a PCIe POST card. They cost a bit more. The are only a few BIOS vendors so can look up POST codes with any similar board (eg all AMD boards use AGESA)

Some PSUs only spin the fan when under load, so no fan spinning is a red herring.

Theo

What brand of PSU out of interest?

I had a similar case recently where a customer had purchased some of the parts to build a machine. It would not boot - but it was clear it was getting standby power (some check LEDs on the mobo were lighting).

He tried all the normal stuff - booting with minimal config - one DIMM, no gfx card, no drives connected etc. Still no joy. It looked like a mobo or CPU failure. So I sent him a new mobo since that was the more likely culprit. Still no go. So in the end I said bring it to me and I will test it. So I setup his mobo on the bench with my CPU and it booted. Aha, must be a dead CPU (very rare IME). So swapped to his CPU just to prove it, and that also booted!

We then though to try his PSU and it failed to boot on either CPU. So it was partially dead PSU. I looked like it was working until you tried to get it to power on - then there was a faint "click" and it shutdown.

So I had another PSU drop shipped to him. It would not boot with that.

Shipped another PSU again (this time a different make), and it all worked fine. So the moral of that storey was it seems like a dodgy batch of PSUs.

(The PSUs were 750W BeQuiet - which I normally find to be very good. Replaced with a Corsair in the end)

These are the very expensive, battery operated, Apple Ski Googles. For when you want to look like you are skiing in the house.

Paul snipped-for-privacy@needed.invalid wrote

Yeah, I know what they are. I was just commenting on your more exciting bit.

Well, I hope the CPU fan spins. I don't think this is a water-cooled PC.

There should be some noise from fans, in a typical build. Sure, you can be driving a Zalman setup (heatpipe computer case), but even those, they really still needed a fan (they could not really do 400 watts fanless, the fanless number was somewhat lower). There are PSU that are completely fanless, PSU with controlled fans with zero speed operation in the response curve, and I just retired my PSU that had a dial to adjust the lowest fan speed (which I always turned up to a nominal level).

The OP was shooting for a large power supply, but I don't know if I have a record of that.

"The selected components so far are:

Asus Prime X670E Pro WiFi AMD Ryzen 7700X 8-core processor Kingston Fury Beast 32GB 8-core socket AM5

perhaps:

Asus Radeon RX6600 Dual 8GB Graphics Card "

"I have been building micro PCs since 1979 so I use my experience."

"It appeared to show the Corsair 850 watt power supply was dead.

I happened to have a 500 watt Zalman.

I connected that to the tester just to make sure that the latter worked. It did. "

"The Zalman is not modular and it produced no additional signs of life. I purchased another 850 watt supply (it is bound to come in useful in the future). The result was the same.

My conclusion was that it had to be the motherboard or the processor. (I discounted the dram). The board went back to eBuyer and was received yesterday. "

"The motherboard was tested OK. The CPU went back and was tested, AND A replacement is being delivered this afternoon. "

"I completed the rebuild today.

Still doesn't work. Nothing except a blue LED on the mouse. <=== +5VSB working "

OK, this was the "plan of record" post.

The RM850x power supply, is zero fan speed up to 340W output. There does not appear to be a control cable for altering fan speed that I can see in the listing.

At BIOS level, there is a tendency to use one core and it can rail on one core depending on what you're doing in the interface. I can be drawing 132W from mains for example, when the popup boot menu is on screen. But this is well less than 340W.

The CPU fan cooling can be dynamic, but at 132W, it eventually spins at a decent rate.

And there is the power LED on the front panel header. That's a red LED on my build (to stand out from the other colours).

Power LED (2x4 FP header) Lights when PS_ON# asserted Traditional Asus green LED Missing on this generation, was tied to +5VSB rail Warning light by ATX12V 2x4 New for this generation. Lights when 2x4 not installed. Staging/debug LEDs Normally four white LEDs in upper right corner, missing on this board. Light in sequence, as BIOS phases progress. Both my machines have staging LEDs of some sort. POST digits Not on this board

It's pretty grubby as indications go. AMD BIOS also tend to be adaptive, and there is more fan response "on firstrun" than perhaps later. I don't really know where the behaviors I've seen, are coming from! Quiescent power on the PC has dropped since I bought it. It OS-idles at 36W, OS-flat out 224W, BIOS start 132W.

Paul

I'm also told that it is possible in the bios to decide on the function of the on off button. However if you cannot get the bios to boot, that does seem to be a bit of a dead area to investigate. However it looks like your

It's also worth scoping the power rails. Dirty power and digital devices don't get on at all well together.

Typically a 150fps massively pixelled video card for ultra realistic call of duty video games.

I am happy running my games on a intel integrated chipset at 1920x1080 at 40 fps that uses about 15W...

You might make fun of that, but my experience on the new system, is traditional power supplies do not have the transient response for the CPU loads now present. My new CPU "wore out" what would normally have been a "good enough" power supply for a computer build. There is now a higher wattage supply in its place. Where I once would have signed off on a 450W for a simple build, I might suggest a 600W in its place today, just so the 224W transient of an Intel on turbo, will be handled without wearing out the supply (too much stress).

The idea then, is the 850W laughs at the smaller CPU transient and should have a long life. Video cards are similarly demanding, and a 4090 going from no-load to 3D_max could be quite a transient as well (up to 600W).

You don't want to go too far overboard on this, but if you find the 12V is lower than normal on "old faithful" supply, it could be that the new computer bits you bought, are just wearing it out. I had a new helium-filled hard drive, and it did not like the low (but still in-spec) power supply voltage. That was part of the incentive to fit the spare supply, which kept the helium drive happy. The helium drive seems to have a tighter spec on voltage than the rest of my fleet. (Normal drives will operate down to 11V before the low-voltage-detect causes them to cycle or turn off. The Helium drive demands better, for no particular reason.) The helium drive is for backups, and the boot drive is SSD.

Paul

Yes, it's generally good not to run the PSU right up to its maximum rating. Also, the rating is based on adding up all the rails - it might give you 20 amps at 5V, but that's 100W you can't use for your graphics card (which is mostly 12V powered).

The PSU should be specced for everything running at max power and then a bit of headroom besides. While in general energy efficiency has got better over the years, peak power can still be high.

Theo

Which is why I am transitioning to computers that don't use power hungry Intel chips. My previous desktop has a Nvidia card and a power hungry CPU and kept the room warm all winter, This one has a core i5 I think with onboard graphics that runs faster and uses about one quarter of the power. Currently its just showing 25°C for the chipset. I never hear the fan come on.

It probably is running at less that 20W.

My new ARM based server looks set to be under 10W.

Electricity is expensive. And how much CPU power do you actually *need*.?

I wanted something for 7ZIP compression, and that is about all it contributes to. It's surprising how many other softwares are single-threaded.

What's really sad, is when I visit a website with Javascript advertising, and my browser bogs down. But as it turns out, this is the fault of the OS I'm using. Changing the OS tends to fix the problem. I think it's remotely possible the browser threading model is not the same, on each platform.

Paul

Then what use is a multi-core CPU?

JavaScript is utter s**te. No two browsers interpret it exactly the same. And it represents a pretty massive security hole.

And the 'frameworks' that are designed to enable total numpties to generate cross platform websites for e.g. banks are even worse.

And yes, how javascript implements threading has to be OS specific.

When you run multiple long-jobs, then you can run more of them. That's what servers do, after a fashion.

I have sufficient capacity to run multiple VMs on here. I could have, like 20 VMs on here :-) My "personal best" for VMs though, is only running three at once.

When I run multiple VMs, it's usually SAMBA file sharing tests. When it breaks, it's never-twice-the-same.

Idle power consumption is 37 watts (measured).

Paul

Mmm. I calculated that an ARM based unit with only a 10W PSU would do what I need server wise.

So at least 27W over 24 x 365 hours saving.

Which is nice, but if you need the CPU horsepower even a medium sized x86 (i5 etc) is going to have a lot better performance. So it boils down to whether you need the horsepower or not - and if you do, whether you're prepared to pay the electricity cost for it. If you don't then a low power system (Arm or x86) is fine for you, but if you do then x86 has a lot more options.

There are x86 systems with similar idle power to a Pi, but much higher peak power/performance, so it is possible to only pay the power cost when you need it. When you don't, they're only marginally more power hungry than the Pi. Once you start needing 170W peak CPU power then the idle power nudges up to 10-20W, but that mean be acceptable if you do need the 170W compute occasionally.

(Another annoyance with the Arm boards is limited RAM, which can be annoying if you want to run multiple VMs/etc)

Pick the right tool for the job, in other words.

Theo

Total agreement. My server runs as a file server, as a media server and as a TV server. Only the TV server uses CPU. The current one that will be replaced is a core 2 duo at 3GHz with an Nvidia graphics in it. Runs pretty hot.

This desktop is a core i5 6600 2.70GHz × 4 with 8GB RAM

Its the fastest processor I have had , it was second hand and the case barely gets warm. It's a dinky little HP EliteDesk machine Lees than £250 refurbed.

Indeed. For me it is really horses for courses.

I am simply retiring the old tech x86s to 'occasional' use.

One good x86 for the desktop and hopefully one good Pi3B for the server

And a laptop.

I don't think ARM will run much in the way of VM.

I don't yet regard them as suitable desktops although the Pi 5 looks pretty damned good

But they make fabulous little servers and utilities. And components for larger projects.

Exactly.