Intel CPU/IGP throttling on 1080p/4k workloads

[prankstare]

This is a curiously new behavior I have to report in case somebody knows what's going on.

Personally, this is the first time in years I have purchased an Intel-based product, the Intel i5-4250U and whenever I would play some random 1080p video, the CPU/IGP would throttle a bit (fan gets considerably louder). But then after I bought a pair of decent dual-channel memory kit, the symptom disappeared completely.

Has somebody experienced the same problem with Intel embedded graphics solutions? I find this rather funny fact especially due to the fact that the processor would get substantially hotter if not working in dual-channel memory mode.

 

[Kursah]

That embedded graphics solution takes advantage of more and faster RAM. I have a 4200u and it was noticeable going from 4gb1333 to 8gb 1600.

What do you mean by throttle? My 4200u throttles to a non-turbo max 1.6Ghz when it reaches 72c. Still been plenty for my needs out of that device.

The fan will get louder as the temps increase for sure...and once you reach the programmed throttle temp limit...well you'll go back to max nom-turbo speed.

Regardless...the ram upgrade probably gave your OS the workspace it needed at a speed the CPU could utilize for better pwrformance.

 

[prankstare]

Hi! Thanks for the reply!

What I mean by throttle is the CPU would clearly try to reduce the clock on some of its active cores as the CPU utilization would constantly max out at 95-100% on 1080p/60hz video playback (say Youtube for example). I'm sure this isn't about lack of RAM, but speed RAM as you put it.

What I find most curious about this is that I have heard people talking about slower parts of a machine trying to keep up with faster parts (in this case, HDD in relation to CPU), but never expected throttling to happen if for instance the CPU/IGP runs out of bandwidth (in single-channel mode). I mean, the 95-100% CPU utilization plus increase in temperature is quite weird considering a simple 1080p/60hz video playback.

Anyhow none of these symptoms have shown up after I upgraded to a decent dual memory kit.

Just a curious observation.

 

[OneMoar]

wasn't throttling it was simply running out of memory bandwith

 

[prankstare]

wasn't throttling it was simply running out of memory bandwith

But then how would you explain the increase in CPU temperature?

I know the HD5000 is more than capable of handling HD playback.

 

[little cat]

But then how would you explain the increase in CPU temperature?

I know the HD5000 is more than capable of handling HD playback.

The dual channel memory eases the iGPU and the CPU - faster data fetch thus CPU work time at higher clocks drops and thus the temperature . My guess .

 

[Aquinus]

But then how would you explain the increase in CPU temperature?

It's conceivable that pushing a single channel on the memory controller puts far much more stress on the IMC than splitting the load between two channels which may not require DRAM to be clocked nearly as often. The width of the bus in dual channel merely might require fewer clock cycles to do the same job to read and write data from system memory. The CPU might get work done faster and in turn spends more time in a low power state versus running full tilt waiting longer for data. iGPUs tend to be bandwidth hungry which is why the higher end Iris Pro has the eDRAM cache which improves cache hit ratios by up to 95% on certain CPU workloads.

 

[prankstare]

It's conceivable that pushing a single channel on the memory controller puts far much more stress on the IMC than splitting the load between two channels which may not require DRAM to be clocked nearly as often. The width of the bus in dual channel merely might require fewer clock cycles to do the same job to read and write data from system memory. The CPU might get work done faster and in turn spends more time in a low power state versus running full tilt waiting longer for data. iGPUs tend to be bandwidth hungry which is why the higher end Iris Pro has the eDRAM cache which improves cache hit ratios by up to 95% on certain CPU workloads.

This is the kind of technical answers I expect to have.

Thank you!

 

[jaggerwild]

But then how would you explain the increase in CPU temperature?

I know the HD5000 is more than capable of handling HD playback.

Why don't you list your full system spec's so we can better help you out, also list the CPU cooler?

 

[prankstare]

Why don't you list your full system spec's so we can better help you out, also list the CPU cooler?

It's solved already, mate.

No need to worry.