Dell M4800 CPU locked in low power state

Does the system correctly identify the AC adapter, or does it show "unknown" in setup (F2 at powerup)?

If the AC adapter is not correctly identified (or is a non-Dell third party adapter), the system will run as if on battery all the time -- keeping the CPU speed exactly as you see it.

Anyone got a solution for this?

Hi Dickie,

What operating system is installed?  If you haven't already, I would suggest flashing the BIOS:

www.dell.com/.../driversdetails

I would then try disabling C-States and SpeedStep in the BIOS/setup. If it's still the same, what happens if you try a clean boot?

support.microsoft.com/.../how-to-perform-a-clean-boot-in-windows

Let us know how you get on.

Thanks

Thanks for the reply. It's running Windows 10. I have updated to the latest BIOS but that didn't fix it.

I tried disabling SpeedStep and C-States, and that unlocked more mutipliers, although it didn't seem to want to run above x29. I then tried just with SpeedStep disabled and it was running up to an x38 multiplier (the true maximum). In both cases, with Prime95 running, the CPU strangely dropped down to an x23 multiplier.

I don't really want to run it like this though as the drain on the battery will be much higher. What can I try to get it running with the full range of multipliers?

Enable SpeedStep again, then boot to Windows and open MSCONFIG.

Select "boot" > "advanced options" then check the "number of processors" box and select the maximum number of CPUs.

Hopefully that should do it for you.

This solution partially worked but not entirely - now when it is running on battery it has access to higher multipliers, but as soon as I plug in the charger, it goes back down to 8x and will not budge from there.

Can anyone suggest a fix?

Given the last description, first try a new OEM Dell adapter -- 130W for integrated video or 240W for discrete.  If that doesn't solve the problem, replace the DC power jack.  If that doesn't solve it,  the issue is with the mainboard -- which is expensive to replace, but likely the only solution to the problem.

The power adaptor that it came with was 130W. As it happens I did have another one around, but the results were the same with that.

I tried it with Speedstep disabled and the laptop will run a 30+ multipler with the charger plugged in. Would it do this if it had a damaged port or motherboard?

Disabling speedstep should cause the CPU to run as if on battery all the time.   With each piece of evidence, it's becoming clearer you have a faulty system board.

From my second post: "In the 'battery information' section, it says 'AC Adapter = 130W'. It is the original Dell power supply."

Is there some further information that shows if the system is identifying the power adaptor?

Would this also explain why GPU-Z is reporting that the GPU is running 405MHz due to a power cap rather than the 666MHz it should be running at under load?

It depends on the "this" you're referring to.  No, it can't be the disabling of speedstep -- that affects ONLY the CPU.  If you have a power fault on the mainboard (i.e., a faulty power circuit or clock crystal), then yes, it could explain the slow CPU AND the slow GPU.

Since CPU failures are exceedingly rare vs. mainboard failures - and a CPU plus GPU failure even less likely, it's very likely that (assuming as above, the system DOES correctly identify the AC adapter -- you've never answered that question) -- that it's the mainboard that's faulty.

No, that's about it (I saw it in another post from a reply but missed it in yours -- sorry).  Everything points to a bad mainboard.