Capped CPU speed at 30%

Hi NasMaximus,

Can you try updating the BIOS?

www.dell.com/.../driversdetails

How recently did you notice the drop-off in performance, or has it always been like that?

The 5510 requires a 130W AC adapter or a USB-C/Thunderbolt connection capable of supplying that much.  Are you using a lower-wattage AC adapter, or is your current AC adapter maybe not supplying that anymore?  If you reboot into the BIOS and go to the Battery Information section, it will show you the detected wattage of the adapter.

Otherwise, go to Power Options > Advanced settings > Processor power management and make sure the maximum processor state setting is 100%.  I wouldn't recommend changing the minimum.

If this only happens after you've been doing tasks that run both the CPU and GPU intensely at he same time, then it's possible you're seeing thermal throttling.  Are the fans running loudly when you observe this slowdown?

Hi both, thanks for replying.

All Dell, Windows and Adobe updates have been installed including the latest BIOS to V1.4.

The slowness in particular I noticed was after a major Adobe update. I've been on remote assistance calls with adobe twice now (total of around 6hrs) trying to figure it out.

However, I just noticed this CPU capping yesterday.

I user this Dell Thunderbolt Dock which is rated at 180W:

http://www.dell.com/en-uk/work/shop/dell-business-thunderbolt-dock-tb16-with-180w-adapter/apd/452-bcpb/pc-accessories

Although Ive just noticed this paragraph in the details for it:

http://www.dell.com/en-uk/work/shop/dell-business-thunderbolt-dock-tb16-with-180w-adapter/apd/452-bcpb/pc-accessories

Hi, I've just checked on the actual adaptor that came with the block, and its a 240W, my mistake.  The laptop came with it's own 190W power adaptor anyway which I rarely use.

I plug the TB16 block into the laptop via a thunderbolt connection.  

However, I have this afternoon tried the laptops own 190W power adaptor by itself and the CPU is still capped at 30%.

I've already looked into the power management settings.  I did at one point try the minimum speed at full throttle, but it didn't make a difference either.

I never hear the fans running at all unless I put my ear right up to the vents underneath.

You can verify how much power your laptop is getting by checking the Battery Information section of the BIOS as I already described, but when used with a Precision 5510, the TB16 dock must have a 240W adapter in order to provide full power to the laptop, otherwise the system will significantly throttle CPU performance, especially when the discrete GPU is running.  It may even continue draining the battery in that situation since it can attempt to DRAW power from the battery to make up the shortage of AC adapter power.  The TB16 is sold with 180W and 240W adapters, and you simply bought the wrong one.

I would not recommend plugging an AC adapter directly into the laptop while the TB16 is also connected.  That's required for Precision 7000 Series models since their power requirements exceed what can safely be sent over a Thunderbolt cable at all, but for other models I believe that's specifically warned against in a manual somewhere.  But if you want to disconnect the TB16 to check throttling in that configuration, then yes that would be an appropriate test

The AC adapter requirement for the TB16 is shown in its FAQ page here: www.dell.com/.../dell-thunderbolt-dock--tb16--information-and-specifications

As a follow-up to the above, the dock itself is identical regardless of which AC adapter it comes with, so if you can't return the TB16 anymore or it would be too much of a hassle, you could technically just buy a Dell 240W AC adapter from Dell or a reputable third-party seller and use that.  The 180W adapter that you currently have could then be kept as a spare for plugging directly into your system if ever required, although doing so would require this DC Power Dongle: www.dell.com/.../pc-accessories

Ok, well you might still want to check the BIOS to verify that the system is actually receiving at least 130W.  You'd probably see warnings if you weren't, so it's probably fine, but it can't hurt to check.  If the fans aren't running, then it's not thermal throttling.  In Power Options, I forgot to also mention the System Cooling Policy. Make sure that's set to active, because if it's passive then the system will only allow the components to run as fast as possible without requiring the fans to come on.  If all of that still looks good, check Device Manager to make sure there aren't any unknown devices since there are drivers that are involved in managing CPU performance and could possibly cause throttling if they're not present.

No problem, thanks for the update!

Hi Alasdair, I've just got off the phone from Robin in technical support, after a good hour or so of testing, he's put it down to a motherboard problem and is booking an engineer to replace.  It will report back when this has been done and let you all know what the outcome is.

Hi NasMaximus,

Please send me a PM with your service tag and contact details. I'll look into it for you.

Thanks