Clevo P750ZM: GTX 980M Overclocking Investigated
by Jarred Walton on March 20, 2015 10:00 AM ESTGTX 980M Overclocking: Do the Time Warp
With the overclocking results in hand, it’s not too difficult to see why people would be upset with NVIDIA locking out overclocking on mobile GPUs. Using the Clevo P750ZM from Eurocom (aka the Eurocom P5 Pro), we were able to easily increase clock speeds on the GPU by more than 10%, and a 20% boost only required the use of an unlocked VBIOS. If NVIDIA follows their usual pattern, the overclocked GTX 980M is likely going to be faster than the next halo mobile GPU from NVIDIA, whenever that shows up (probably in the fall).
Hefty, hefty, hefty...
With those results in hand, NVIDIA’s decision to lock down mobile overclocking might seem like a way to prevent users from getting a free performance boost, but there’s more going on. The biggest concern is that we’re using what is arguably one of the best platforms for GTX 980M overclocking in this article, and while the results are great I wouldn’t count on all notebooks using GTX 980M being able to achieve similar clock speeds.
Case in point: the Gigabyte P35W v3 discussed on the previous page. Depending on the game and settings, the CPU can be a bigger bottleneck than the GPU, and particularly at lower resolutions (e.g. 1080p) the GTX 980M needs plenty of CPU power. If a CPU has to throttle down to lower clock speeds due to excessive heat, overclocking the GPU isn't going to help much. Our stress testing of the P35W v3 seems to have encountered this scenario, and there are times when just running a game on its own can trigger CPU throttling.
Thin + overclocking = questionable
As with any overclocking attempt, the final stable limit will vary even with the same core hardware. We managed a 20% GPU overclock without too much difficulty on the Eurocom P5 Pro (P750ZM), but other P750ZM notebooks might do better or worse than our sample. The Gigabyte P35W v3 with the stock VBIOS also managed to max out the GPU overclock (around 12%), though the benefits aren’t as great thanks to the slower CPU and less robust cooling.
The big question is going to be what overclocking might do to long-term stability and component life. Running the fans in the P750ZM at 100% keeps the GPU running nice and cool even when overclocks, but it could cause the fans to wear out sooner than expected. Having the CPU run in the mid-90s is also a concern, so you might consider buying an extended warranty (even if you don’t plan on overclocking). And while we didn’t have any problems with our P750ZM during testing, we’d be remiss if we didn’t note that we’ve had more than a few high-end gaming notebooks go belly up over the years.
Only NVIDIA and their partners know the exact numbers, but it’s possible NVIDIA has been seeing unacceptably high numbers of mobile GPU failures and locking down overclocking by default would certainly reduce the number of people willing to pursue that route. The true enthusiasts meanwhile can still get what they want by purchasing notebooks that aren’t locked down (e.g. the Clevo P750ZM). Just be careful how far you push the clocks, though, as if you burn out a mobile GPU like the GTX 980M, buying a replacement can cost as much as a desktop GTX Titan X GPU.
There’s a corollary to the overclocking discussion that’s also worth mentioning: underclocking. Sadly, we’ve seen more than one gaming notebook over the years where running stock clocks proved to be difficult if not impossible with certain games, particularly once the notebook is a year old or more. Mostly that has been with mainstream GPUs (e.g. GT 750M and similar), and underclocking by 10-20% will typically fix the problem. We’ve seen others mention this problem as well, and if NVIDIA fully locks down the clock speeds on mobile GPUs it could create unintended consequences for those trying to underclock.
The final tally is that after backlash from the buyers, NVIDIA has decided to not lock out mobile GPU overclocking in their drivers – and true to their word, the latest 347.88 beta drivers allow mobile overclocking again. (The P35W v3 OC testing was done with those drivers.) We might see NVIDIA try to limit overclocking in the future, but hopefully they stick to using a locked VBIOS. That would allow the notebook manufacturers to choose whether or not they want to support GPU overclocking, and that’s probably the best approach as ultimately they’re the ones dealing with RMAs.
And let me end with this warning: I have burned out GPUs in notebooks in the past, even without overclocking, doing stress testing. It’s a terrible feeling to have a notebook suddenly refuse to boot, or crash as soon as the graphics drivers load. While getting a “free” 20% boost to frame rates is definitely nice, replacing/repairing a dead notebook is not. Discretion in this case is not a bad thing, and overclocking a notebook GPU just because you can isn’t without risks.
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CrazyElf - Friday, March 20, 2015 - link
To be honest, laptops probably don't have the margins for overclocking that a desktop would.For the desktop CPU, it is already pretty hot to begin with. You might be able to knock 15-20C down by delidding that 4790k, much like a desktop. The problem is, with a desktop you can use a giant cooler like the Noctua D15, or water cool. You cannot with a laptop.
GPUs have similar problems. Large triple slot coolers and water blocks are available - indeed they are made specifically for desktop overclocking. There's no way to do that in a laptop. It just isn't possible.
Khenglish - Friday, March 20, 2015 - link
Did you see the GPU temps? With a 20% overclock it only reached around 77C, which is cooler than many stock coolers on similar desktop cards.CPU temps are bad though. I think the problem is that clevo went with a combined GPU/CPU heatsink for this laptop, which is something they have not done before. While this sounds good at first, it makes having good die contact on both CPU and GPU nearly impossible without a large amount of flex in the heatsink, which the P750ZM heatsink does not have.
CrazyElf - Friday, March 20, 2015 - link
Apples to oranges. Maxwell is a pretty cool running chip on desktops too. If you are comparing the 980M to the AMD 290X, then yes, the desktop chips are hot in comparison. But remember, we should be comparing the 980M to a desktop Maxwell, and this is a chip that has 1/4 of the units stripped (so 1536 out of 2048 active) compared to the desktop part, which is already pretty cool running.A delid as I said might solve the problem partly like in desktops of the 4790k, but either way, there isn't much OC headroom in that chip even with the delid.
To be honest, the GT72 is a better choice IMO:
http://www.anandtech.com/show/8694/msi-gt72-domina...
The CPU runs cooler and the battery life is better, should you ever need it. It is somewhat slower, but not by much. Plus newer versions with an IPS screen are available - I just wish Anandtech had reviewed it with the IPS screen.
I just wish that instead of overclocking, that a full 2048 version of the 980 were available, running at a lower clockspeed. My wet dream would be the big 3072-Titan X die severely underclocked on a laptop, but that would never happen for various reasons.
Khenglish - Saturday, March 21, 2015 - link
Yeah full 2048 would rock. I am 100% convinced that the only reason it just has 1536 running is so Nvidia can release a fully enabled chip in the future and say they have a new, faster card.JlHADJOE - Saturday, March 21, 2015 - link
Actually, looking at the combined CPU and GPU temps, it's pretty obvious that system is more or less maxed out thermally.The CPU is pegged at 95-99C, and the GPU is similarly pegged at 77C. When the GPU clock is raised is that the CPU clock goes down, so "overclocking" here merely trades CPU clocks for GPU.
Not that it's a bad idea really, as shown by the game benchmarks, but it does show that there is close to no headroom at all in the Clevo's combined thermals.
Hrel - Friday, March 20, 2015 - link
I think overclocking with today's hardware is stupid, I have no interest in it. I tend to agree with Nvidia on OC.However, that doesn't mean they should go so far as to BLOCK people from being able to do it. Ultimately once they've bought it, it's their choice. At least it should be.
Have OC void the warranty and be done with it. There's no reason to do anything more than that. "You wanna overclock? Fine, do so at your own peril. We wash our hands of you".
This attitude would bring their position from being the right one for 99.9% of the market to 100%.
will54 - Friday, March 20, 2015 - link
I thought they already voided the warranty on OC's or is it just when you go with a modded vbios that they void the warranty ?Buk Lau - Friday, March 20, 2015 - link
Nice work Jarred, glad to see authoritative sites like AT starts to acknowledge OC on mobile GPU! Although you still didn't test with USB 3.1 ports on this machine (so you didn't have peripherals available?)... and in the future I would recommend when you are doing stress tests, just run Prime95 and and Furmark instead for maximum heat on the system. Running Prime95 and tombraider at the same time actually reduces CPU load, because floating point calculation requires much higher work load than game physics. That aside you did a fantastic job! Funny when you noted on potential reasons why Nvidia blocked OC, every generation some cards are just rebrands of old cards with a slightly higher clockspeed. So essentially you can get a free upgrade yourself when you do that, and OC damaging the gpu might not as much of a threat if Nvidia is doing it themselves every generation LOLajc9988 - Friday, March 20, 2015 - link
I disagree with your choice of tests. Max heat isn't the goal with a laptop UNLESS YOU LITERALLY PUSH THE HEAT ON YOUR MACHINE DAILY FOR ITS INTENDED PURPOSE. I had to change the way I thought about overclocking when I came to a laptop. It isn't about max heat like desktop testing (which now reflecting on it is a little stupid if you never do real world activities that push it like that). You want to test max heat for real world type tests. Anything you may do (x264 for avx encoding, etc. There is a long list of stress tests that fully stress the machine without giving synthetic instruction sets to push the hardware to a heat max.). Also, Furmark and Kombuster are vbios blocked in the premamod bios.JlHADJOE - Saturday, March 21, 2015 - link
Yipes! Close to 100°C on the CPU. That is insane.They should run heatpipes to a round metal plate where you can set a mug somewhere on that thing. Cools the CPU, and keeps your drink warm!