P157SM/NP8250 CPU downclocking when GPU & CPU under load for while

So I got this odd issue that started a few months back.

I mainly use my laptop for working and playing BF4.

I noticed that when playing BF4 my CPU will go from the use to be stable consistent turbo mode 3.4~GHz down to low 2.xx and often 1.xx and remain at that until I quit the game or get rid of GPU load.
I have the 4900MQ so it shouldn't really dip below 2.80GHz ever and it use to ALWAYS run steady stable at 3.4 when in games.

It's not a temp issue as CPU will be in the 60's at that time and GPU in the mid-upper 70's. It even makes the fan speed slow down because it starts to cool off so much with the limp CPU.

I'm not overclocking and reinstall of Windows didn't help.

Anyone see similar before?

I've tried throttle stop and other things and they get the speeds back up but it becomes very jumpy at that point with the speed jumping up and down.

Could this be some sort of power limit/issue? Would a PSU not providing enough current do this or should it simply shut down if it was at too much load? I checked with a meter and it shows 18.94v with nothing plugged in so seems within spec for 19v, just not sure how stable it may give current.

Other specs in sig. but just trying to figure out why this is happening lately. I can peg the CPU or GPU independently fine but both together and at a short while the CPU does that mess.

 

Is it switching to battery mode?

 

Looks like a PSU issue.. I would contact your reseller and have them send you a new PSU.. Otherwise, you might need a new motherboard...

 

Not really.

I have caught it randomly a few times where the green light will turn orange and show it's charging the battery but I don't think it ever really goes to battery mode as the GPU clock doesn't drop down like it does on battery.

PSU isn't covered by warranty after 1 year. I have 3yr extended warranty so MB would be covered but not sure what the cause is. Don't have a spare PSU I can test with.

 

Is the battery level dropping at all during it? If it is then it's the charger as it may be drawing a bit from the battery.

 

If anything was overclocked, or even if he's got the 880M and the 4910 CPU, it likely could be that under heavy load with both CPU and GPU maxed out (which BF4 potentially can do) that it's drawing more power than the brick can provide.

Remember, the 8258/8268 only has 180W power supplies. It's been proven that under heavy load it could peak above that with an 880M and a higher end CPU, and most assuredly if you overclock either.

Anyway to monitor the power draw into the laptop?

Someone mentioned that there's a Dell PSU that works with the Sager/Clevo that can put out 230W of power. This would solve any issues, especially if you overclock.

 

It has dipped down to like 98% and charge back up but that's about it and not very frequent. Maybe I catch it doing that once every other week under heavy load.
What's odd is these laptops don't support pulling from battery and AC at same time. I thought only some of the MSI and other ones did for those so called "turbo" type modes for more power.

I didn't use to have this problem though.

I played BF3 and BF4 on this laptop when I first got it and it was fine. It's only over the past 5 months maybe it started. I just got time to actually dig into it more and catch that is what is causing my studder and random lagging in the game.

No other adapters will work with this laptop without modding them and fwiw I shouldn't have to. IF I am NOT overclocking this should be designed in a way I can use it from the factory at full speed they designed it for. Now grant it I know the CPU's are limped some down to 71amps instead of the 95 they should but that just impacts turbo. So instead of steady 3.6GHz factory we get like 3.4GHz. Which is whatever, but this darn thing is now going down into 1.08 and even a few times 0.90Ghz... :/

If it was hitting the battery all the time it would make sense the MB circuit maybe or the charger is bad but it's not. Maybe once every two weeks but heck, my old P150HM use to do that under heavy load too.

I agree though, they ride these 180W to the limit. I hate clevo for not using the same power input as the others so we can use better PSU :/

~122w GPU
~47w-58w CPU
and that is all the 180w psu right off the bat. The GPU is throttled back from the manufacture speed wise to like 771 instead of 823 because of the whole more power (old ones use to be 100w) so even if you say 47-48w + 100w that doesn't leave much for mobo, display, led's and a few USB, 4 stick ram etc.

But I just don't get why in the last 5 months am I having issues short of something has changed or is going bad. Either MB or PSU

Further, I have the onboard screen disabled (I use external) so it should be saving a little power with that even. I also keep the backlit keyboard LED disabled as well and only have the one SSD and Bluray drive in it.

 

I sincerely think it is your PSU as well. I can confirm that I do NOT experience that issue at all, even with OC'd GPUs. Single 330W adapter here. Also, your 4900MQ should be running at 3.6GHz constant, not 3.4GHz. From the start you should have noticed.

Also, you should try using the modified vBIOS for the 780M. Just as a general suggestion. It performed much better for me after I did that. But seriously, something is definitely wrong. You should mention this to your reseller and see if they think it's a PSU or motherboard issue. If it's a mobo issue, great. If it's a PSU issue, I'd suggest getting a 230W PSU from the P17xSM or P17xSM-A series if you're buying a new one. Good luck!

 

This looks like a PSU issue to me. I experienced this issue when i try to run prime95 + furmark with OC'ed 780M and non OC 4800. I used 240W psu, but PSU cut off (trip'ed) due to load and notebook switched to battery. PSU didn't restarted until I on/off wall outlet.

Make sure your PSU is not cut off.

 

I don't think I need to mess with modified 780M vbios as the issue seems to be more the CPU or power. I've tested OC GPU and stress test it alone and it's fine, same with CPU alone it's fine. Both together equals the trouble.

A 4900MQ won't sustain 3.6GHz with 4 cores or peak to it even on the 15" models due to the current limit of 71Amps. This is the sneaky way these manufactures use too small of a PSU by limiting performance.

The 780M is reference clock of 823, clevo uses it at 771. The 4900MQ is reference current of 95Amps. Clevo uses 71Amps. This is how they get away with an 180w PSU :/ limit the performance.

That's just it. I expected if the PSU was the issue it would trip or turn off but it never does. Stays on blue light running. The laptop never really shows it switching to battery either. It's just once in a blue moon I noticed the battery level drop under hard load, but now that this issue is happening that doesn't happen anymore and even when it did was maybe once a week tops with heavy daily usage.

I wish the PSU would trip so I would know it was that lol. Just don't want to mail this sucker across the country now and be without for a few weeks.

 

Can you point out to me a 780M that was 823MHz without boost? I have never seen a single 823 base clock 780M. Ever.

Also, my 4800MQ uses 71A as its current... I've also never seen them be 95A stock, and the 4900MQ only has 2MB extra L3 cache and 100MHz extra core clock at stock. Again, I've never had downclocking issues like what you've experienced unless I downvolt my CPU a decent bit. Hell, it sits at 3.5GHz with -50mV on the core, and stock 71A. So... yeah. I don't get why yours is not working as intended. Can you show me where 95A is reference for a 49x0MQ? I think it's reference for the MX... but not MQ.

Finally, the 780M simply works better with the modified vBIOS; it locks it to 850/5000 and disables dynamic boost, so it runs flat at 850/5000 once it's in 3D performance mode. The modified vBIOS was actually necessary for me so my 780Ms would draw enough power to support my 120Hz screen. I know this likely does not bother you, but still, I would again recommend that vBIOS.

 

Max current levels are motherboard dependant, IIRC alienware are higher at stock but are locked down so become a limit for higher clocks. It should be ok for stock levels and it's unlocked so you can tweak it

 

OP, honestly to save yourself some trouble get a 230W Clevo PSU and see if these issues are solved.. Much better then loosing your laptop for a few weeks...

 

The Clevo 230w won't work, wrong connectors. I've only seen adapters to go from the dell PSU to clevo size. Not wrong clevo to right clevo.

Plus this is all dumb, if I am running stock I shouldn't have to use larger PSU, mine should work. I just wish I had another to test if it's PSU or MB.

Not the time of year I want to go blow $100 on a maybe :/ esp if I have to mod the darn PSU on top of that.

 

A healthy power brick would not be doing that, it seems like it's not quite as efficient as it should be and strugling to keep up. A healthy power brick would mean a 3-3.1ghz CPU and at least regular clocked 780M under very heavy load.