i5 4670k downclocking randomly

[fishingcat]

So my i5 4670k that I got last week has started exhibiting some weird behaviour, causing me a ton of lag.

It's downclocking to around 800Mhz frequently, which causes lag doing almost anything. Moving windows around, even scrolling can end up lagging while the chip does it. In game it clocks up to full speed, but again, randomly downclocks occasionally to 800Mhz to around 1.6Ghz.

I've reset my BIOS to stock settings, but the issue persists. Temperatures are low (sub 50 degrees at load on stock, sub 70 overclocked) and there aren't any PSU issues (EVGA 650W).

Any ideas what's going on here and how I might fix it?

 

[coolpurplefan]

Is there a power-saving setting in the BIOS?

Out of curiosity, what kind of motherboard?

 

[ShintaiDK]

800Mhz is default idle mode clock and doesnt cause problems.

Lag by moving windows around and scrolling tends to be a GPU issue.

 

[BSim500]

800Mhz is default idle mode clock and doesnt cause problems. Lag by moving windows around and scrolling tends to be a GPU issue.

^ As Shintai said, 800MHz (plus the intermediate states (1.6GHz, 2.4GHz, etc) is perfectly normal when not under load as part of SpeedStep which drastically reduces CPU energy consumption when idle. Laggy scrolling & moving windows, etc, sounds more like your GFX card isn't "upclocking" when it needs to (they do the same as Intel's Speedstep - underclock & undervolt when idle) or the GFX driver's threshold isn't sensitive enough. Many use Speedstep just fine without any lag.

 

[fishingcat]

You see, I had kind of assumed it was a GPU issue earlier, until I saw the huge lag spikes in game with the CPU dropping to 800MHz.

As it stands though I think you're right. My R9 290X is idling at 1030MHz core (which is totally inexplicable, since it should be 425MHz at idle) and 150MHz memory, which just isn't enough to drive two 1440p monitors smoothly. I've just done a clean install of the GPU drivers and it's still happening, so I have no idea what the hell is going on. It wasn't originally doing this either.

EDIT: I have no idea what the hell is going on actually. My CPU was still at 800MHz while I installed MSI Afterburner, and took an extremely long time to clock up to full speed when I ran AIDA64 (it was visibly going through the clock speeds one by one, taking a couple of seconds between each, from 800MHz, 1200MHz, 1600MHz, 2500MHz etc.), which I think is the cause of a lot of my lag. However the GPU clocks are also behaving extremely oddly, with very low memory clocks most of the time, and a full core clock at all times. Since this persists even after a driver reinstall I have no idea what is going on.

 

[fishingcat]

More updates ahoy!

So I've managed to force my GPU clocks to maximum using MSI Afterburner alternative overclocking without powerplay support (for the record this is a terrible idea for normal usage, since it uses a ton of power and results in idle temps of nearly 60 degrees). This isolates the effects of GPU downclocking from those of CPU downclocking. I've been able to firmly establish that the lag that I have been experiencing is the result of CPU failing to clock up when needed.

Switching channels in IRC, moving windows around, watching videos... all lag. The CPU is at a firm 800MHz in CPU-Z and simply isn't rapidly increasing in clockspeed to meet increased demand as it should. Games and benchmarks force it up eventually, but it takes a significant amount of time to get there, and still downclocks randomly in game, causing huge slowdown.

The system is noticably snappier on launch when the CPU is clocked at a full 3.4-3.8GHz during the startup period, but becomes sluggish upon downclocking.

Any ideas at all on what to do here? I'm using an ASRock Z87E-ITX mobo.

Thanks.

 

[BSim500]

Any ideas at all on what to do here? I'm using an ASRock Z87E-ITX mobo. Thanks.

Hmmm. Have you forced just your GFX card's GPU up and not GPU memory as well? When things get "laggy" like that it could be (as you said yourself) the GFX memory is still stuck (not the GPU core). I've had problems with AMD drivers doing that on other cards in the past (sticking the memory at 150MHz idle whilst GPU core upclocks fine).

To rule out the CPU, you could go into your BIOS and disable SpeedStep - see if that works. That would run it at max constantly though. Or do it the "soft" way of Control Panel -> Power Options -> High Performance (instead of Balanced)? It's still not normal for it to lag like that though, even with it enabled. And it certainly shouldn't take seconds to move between SpeedStep states - it should be done in literally microseconds. Maybe there's some "Advanced SpeedStep" latency setting in the BIOS that's been accidentally altered? Short of setting BIOS to default / re-installing Windows / trying other Catalyst driver versions, I'm not sure what to suggest beyond disabling SpeedStep?

 

[fishingcat]

Thanks for the advice, I'm actually just reading your comment after rebooting into windows after disabling speedstep.

Hmmm. Have you forced just your GFX card's GPU up and not GPU memory as well? When things get "laggy" like that it could be (as you said yourself) the GFX memory is still stuck (not the GPU core). I've had problems with AMD drivers doing that on other cards in the past (sticking the memory at 150MHz idle whilst GPU core upclocks fine).

I know for certain that my my mem and core clocks were both at full, since they were constantly at max value in GPU-Z, and I disabled all downclocking via Powerplay. That pretty convincingly ruled out the problem being GPU related in my mind (although I still have no idea why the core clock is idling at 1030MHz now, I'm sure it was 425MHz when I first got this card). I'll blame it on AMD's weird clock settings with multiple displays.

Or do it the "soft" way of Control Panel -> Power Options -> High Performance (instead of Balanced)?

Oh my god windows was set to Power Saver mode by accident. What the hell? Oh my god I think this fixes it!

I'm gonna do some testing and make sure that's what is going on, but I think you nailed it.

 

[fishingcat]

Yep, sorted! It was the Windows power state that had somehow ended up set to power save, which meant it favored downclocking the CPU rather than increasing the CPU fan speed. I have genuinely no idea how that happened, since I haven't even been into the power management screen since putting this PC together.

Thanks for all your help man!