Is the 180W pwr sup enough for a clevo p15*sm with a 780m?

Hi,

I was thinking about buying a laptop based on the new clevo barebones, either the p150sm or the p157sm, and with an nvidia 780m. However, given the power consumption specs of the 780m and the i7-4*00QM, the 180W power supply that comes with these two barebones seems to be a bit underpowered. That's because I believe that the 780m and an i7-4*00QM (even the slowest one) together, can pull at least 170W easily (if not more) by themselves (but maybe I'm wrong).....and I'm afraid that the system would end up
underclocking the 780m or the i7 (or both). I read some reviews of p15*sm laptops and it seemed that during stress tests neither the cpu nor the 780m ever got to their maximum operating frequencies.

Does anyone have any experience/thoughts about this issue?
Would a p170*sm with its 230W power brick be a safer choice?

Thanks

john

 

180W will be enough.

Source: Someone who has used components with far higher power draw than what you want to do on a simple 150W PSU.

Sure, if you try to OC/overvolt the GPU, you may end up pushing the envelope on power consumption, but I have a feeling you'll have too much to worry in the way of temps before you run out of power.

 

I don't know. Maybe you're right, since you had direct experience on these issues.

However, looking at this P177SM, with a 780m and a i7-4900MQ
Review Schenker XMG P703 (Clevo P177SM) Notebook - NotebookCheck.net Reviews

you can see that it hits 209 watts max under stress. A P177SM with its 230w brick can handle it but I wonder what would
happen with a P15*sm. Maybe the p15*sm are set to limit GPU and CPU so that they wouldn't even get to that 209 watts...
(and that's what worries me).

 

The i7-4900MQ (unless I'm remembering wrong) is the highest-performing non-extreme Haswell CPU at the moment. Also, they did not mention whether power consumption was measured at the wall or not. (in which case, we should assume 85-90% efficiency maximum, lowering the actual pulled power to around 170-180W).
A high-quality PSU will be able to supply more than the rated amount, while a low-quality one will be able to supply less.
I would assume that Clevo would have tested the configuration for standard working conditions, but I do agree that, should you plan to do overclocks, you should get the higher-rated PSU.

 

Let's forget about OC for now. Let's suppose that the 180w psu is not enough even for high-stress but non-OC situations
(and thus the system needs to limit CPU and/or GPU max frequencies).
And suppose I used a higher-rated PSU on a p15*sm (compatible plug etc...). Would that be enough to prevent any underclocking? In other words, what I'm asking is if a hypothetical "security" upper limit to the clock frequencies (lower that the maximum capabilities of GPU/CPU) would be "wired" in a p15*sm, (in the firmware or in the electronics of the MB or wherever) thus making the use of a higher-rated PSU useless in a p15*sm.
An higher-rated PSU would certainly work for OC since, if I'm not mistaken, you just change some multipliers and therefore the hypothetical "security" upper limit to the clock frequencies would increase too. But in normal usage, where you don't change any multiplier wouldn't the system limit CPU/GPU even with a more powerful PSU?

But I don't know much on the subject so I may be completely wrong.

 

Those are individual cases that i'm unable to advise you on, and you should head on to the Clevo Lounge for specific information regarding manufacturer restrictions.
However, I still daresay that 180W would be plenty, providing it's a powerful enough PSU.

Regarding ThrottleStop usage to increase TDP/TDC limits in order to clock higher may not be very effective (I had heard rumors that SB/Ivy chips present trouble with throttlestop but have not had time to research this issue). However, I have never known of Clevo to be so restricting as to implement power flow control triggers, and I assume using a higher-rated PSU should work no problem.

 

OK. Thanks for all the info.

 

Running stock you should be golden, if you want to start pushing YMMV since every card will draw different amounts and each PSU will be able to provide different amounts.

I've got a mod guide to provide more juice, though with that you do throw any warranty into a bin........ which sets on fire........ which gets hit by a tactical nuke..... you get the idea.

 

My 8250-S brick has FSP on the back. While I haven't seen many of them recently I seem to recall that back in the day that they were one of the better PSU mfgs, at least for desktops. (I was pretty surprised to see that FSP "logo" on the brick. I was expecting generic OEM or Sager re-"branded"...)

Anyways, look at htwingnut's review. Sounds like unless you're doing any crazy overclocks that staying within Clevo's "specs" that it should be fine. IIRC all the supported/shipping CPUs ATM are all 47W, c. 122W 780m -> 11w for misc + whatever at max ratings...)

 

OK but let's assume thats even without OC, 180w is not enough and the laptop limits CPU/GPU frequencies (I think I recall at least one failure of this kind, I believe it was a dell laptop, alienware?, that just had an insufficient PSU and just cut off clock frequencies). In that case I suspect (but again I don't know enough on the subject) that just using PSU with higher wattage on a p15*sm would not solve the problem and the CPU/GPU frequencies would still be limited.
I mean it's different from power throttling due to overheating since the system gets a feedback from the temp sensors, so a better heatsink automatically guarantees less throttling or shutdowns. But AFAIK there is no feedback on the "juice availability" from the PSU right? So a better PSU would basically be ignored by the system. But I'm just speculating and maybe there is a sort of wattage feedback from the PSU that the system can use to choose whether or not underpower the
CPU and/or the GPU.

 

Yes, I read that review (very helpful) and, quoting:

"780m also comes with Boost 2.0 feature that allows the GPU to boost when the proper temperature and power parameters are met. And to be honest, I never saw the boost speed drop. It runs at 849MHz at stock"

So that reassured me, but then in a notebookcheck review they noticed that the GPU frequency was apparently kept lower than the maximum and in another review there was that 209 watts draw...(however, it wasn't specified if it had been measured from the wall). Hence the doubts

 

The sager is not like the alienware and not aware of the.plugged in adapter rating so you are free to use a higher rated one.