My i7 8550U Behavior Question

Being out of the game for quite sometime I am a little CPU info challenged.

I just purchased the laptop shown in my signature and run a gadget to help me keep an eye on it.
The image below shows what I see allot from the top thread being pegged.
I ran the Intel test utility and it went well not getting hot at all.
Is this normal and a part of this CPU models power saving throttle?

 

If its running fine then its probably just that gadget which isn't working correctly. If 1 thread was at 100% load it would be turboing a lot higher than 1.8Ghz.

 

Download either 'Throttlestop' or Techpowerup's 'HWMonitor'. Run something like Prime 95 with Throttlestop open and check what's happening there - if it's being TDP throttled or getting insanely hot, you'll be able to see it.

If I'm reading the screenshot correctly, you're getting a high single-threaded use but no turbo, as it lists 1.8GHz as the frequency. Temps look OK, so that would be some overzealous throttling in this instance. I'd ensure that Turboboost is enabled in the BIOS and that you have enabled 'maximum power' in the Windows power plan. To be sure, go to power settings and ensure that 'maximum power state' of the CPU is set to '100%'.

 

This is totally normal for the low voltage "U" processors. When loaded, they'll temporarily be "allowed" by Intel to exceed their 15W TDP rating. This last about 15 or 25 seconds (I think - I did some googling, but couldn't easily find the time limits for the cTDP (configurable TDP - there's a higher TDP-UP limit - see here).

After that amount of time (which can be lowered by your device OEM), it will drop back to a 15W power limit, resulting in throttling (and low temps while "pegged").

 

Thanks Guys.

 

The only system I own with a 'U' 15W CPU is a dual core Haswell platform and even when the TDP limit kicks in, the CPU still exceeds the base clock. I just let Prime95 run for 30 minutes and although the system TDP throttled, it leveled out at 17.6W and stayed there - achieving a frequency above the base clock of 2GHz (Although not by much). I can only replicate this by when using Prime95 - other benchmarks don't cause TDP throttling, so far as I've been able to test. Then again, this might be due to the CPU only being a dual core - presumably this requires less power. Tried toggling the undervolt on and off and it didn't have any bearing on the frequency.

The OP's screenshot shows the CPU not even achieving the base clock. Does the Skylake platform or the quad core have any bearing on this? It just seemed odd that their system wasn't even reaching the 1.8GHz baseclock on single core. I haven't had a chance to play with the Skylake platform yet, so this might just be demonstrating my ignorance on this. My apologies for spreading incorrect information.

OP, is the screenshot from when you're running a benchmark/stress test or just during general usage? Seems odd that there's no turbo going on.

 

It's wide known that the new quad-core i7-8550U never will manage to hold clocks with max load on all cores due gimped TDP.

Run Cinebench Benchmarks for the 2nd and 3rd time, and see how the bench score will sink like a stone in water

Faster i7-8650U perform equal in M$ Surface Pro. It will perform about likewise. It’s by design.

 

It doesn't appear to be even be fully reaching the base clock speed on one core - let alone the turbo speed.

I must be missing something here - gimped TDP is one thing but that screenshot looks like turbo boost isn't being used at all - even though the system is almost entirely using one core. Unless that one core is enough to overload the TDP - which seems surprising.

 

From what I read its a power save or efficient type of CPU. I think its normal for what it is.

 

Hey guys, an update. Was waiting for Malwarebytes black Friday deals (buy one get two) and got around to installing this evening.
Installed, scanned, and found some rouge registry entries and a couple PUP's. And blocked and outbound adserve.

Now that pegged thread is not constant. My already fast boots are faster.

 

OP read this thread to see how the i7 8550u behaves

http://forum.notebookreview.com/thr...ing-behavior-on-dell-inspiron-13-7000.809595/

 

Thanks, that's making me happier. I too am not hard on the laptop just some Photoshop and Sony Vegas here and there. My last laptop was purchased in 2010 so this replacement has been a very nice difference.