T420 cpu always at lowest speed unless speedstep is disabled

i5-2540m in my T420 stays at 780mhz at all times unless I go into the bios and disable speedstep. But of course this will mean it will run at full speed at all times, not good for battery life. Think I have a defective unit or what?

 

There have been several people talking about similar symptoms here in the forum. Or at least, I'd call them similar. Windows Experience Index scores that seem low, and some things like that.

I wonder if there is a BIOS issue. The Core i5 is fast enough that many people wouldn't notice during basic use if it throttled.

I'd suggest posting this on the Lenovo forums, and see if there are anyone else who shares your issues.

 

That's exactly what happened with me, just basic tasks seem ok but I noticed a problem when installing large updates with how long it takes. Then I noticed the clock speed and how it never moved. Hopefully they come out with a fix soon.

 

I know this doesn't help, but my T420 with 2540m runs just fine as reported by AIDA64 and allcpumonitor widget, running from 798mhz all the way over 3000mhz depending what the heck I'm up to at the moment.
Everything is stock except the ultrabay HDD.

 

Sprt, it does help in keeping track of how often the issue is experienced. It's good to get an idea of who is having the issue, and who isn't.

 

I am also using the allcpu widget. Either always at 780mhz (speedstep enabled), or 2561mhz (speedstep disabled). It never seems to turboboost either, never goes higher than 2561 this is bizarre.

 

Is your system fully stock (including Lenovo's OS install from the factory?)
Using the stock AC adapter? Have you messed with the ThinkVantage Power Manager settings at all?

 

I posted this in the other thread about low WEI scores, but I'll post it here as well:

Try downloading both CPU-Z and Prime95. Open up CPU-Z and watch the CPU clock, while running Prime95. Does the clock-speed increase?

 

Another way to test is with the CurrentClockSpeed property of the Win32_Processor WMI class.

Bring up a PowerShell prompt and paste this in:

Register-WmiEvent –Query "select * from __InstanceModificationEvent within 2 where TargetInstance ISA 'Win32_Processor' and TargetInstance.CurrentClockSpeed <> PreviousInstance.CurrentClockSpeed" –Action { Write-Host ("Clock speed changed from: " + $Event.SourceEventArgs.NewEvent.PreviousInstance.CurrentClockSpeed + " Mhz to: " + $Event.SourceEventArgs.NewEvent.TargetInstance.CurrentClockSpeed + " Mhz") }

Then run your favorite stress tests, unplug it, plug it in, etc. to see if that PowerShell session reports any change. If Speedstep is working you'll see output in the Powershell window like this that will start to display as speed changes are detected:

Clock speed changed from: 2535 Mhz to: 785 Mhz
Clock speed changed from: 785 Mhz to: 2509 Mhz
Clock speed changed from: 2509 Mhz to: 2535 Mhz
Clock speed changed from: 2535 Mhz to: 1597 Mhz

You can bring up a separate PowerShell window to stress the CPU by pasting in this line:

foreach ($a in 1..2147483647) {$b=1;foreach ($c in 1..2147483647) {$b = $b * $c};$b}

Also note you can view the CurrentClockSpeed and MaxClockSpeed values with WMIC from a regular command prompt using this command:

wmic cpu get currentclockspeed,maxclockspeed

Although the WMIC command is just dumping the current values and not monitoring like the register-winevent PowerShell command is doing.

 

HWiNFO32 Download gives you a really good view of the proc and the rest of the system.

 

Yes, fully stock nothing changed at all. Only thing I've done is added more ram and updated drivers with thinkvantage updates and windows update. Also put a sad in but everything with that is working fine and yes I put the original Lenovo install on it.

 

What Power Manager profile are you using? It sounds like you're using a low power profile. When you open up windows Power Options, what cpu settings does it show for the current profile?

 

It's set on maximum performance, Says 100% for cpu.

 

Did this happen before you did System Update too? It's gotta be some software problem since it isn't consistent with all T420 users.

 

Yes before the system update as well. Reinstalled windows and everything thinking it may fix it but ran some test before i updated everything and the problem was there, then ran all the updates and problem was still there.

 

Call Lenovo then.

 

This is exactly what I asked someone else to do in another thread but the person never actually did it so I stopped responding. If we have all the information then we can help diagnose the issue before approaching Lenovo but to each his or her own.

 

I just downloaded and ran the program, what info do you need?

 

Could you post 6 screenshots. I need one for each of in these situations:

SpeedStep Enabled:
1) Plugged-in to the wall. Balanced Power Profile. Idling.
2) Plugged-in to the wall. Balanced Power Profile. Running Prime95 in the background on all the cores.
3) Plugged-in to the wall. High Performance Power Profile. Idling.
4) Plugged-in to the wall. High Performance Power Profile. Running Prime95 in the background on all the cores.

SpeedStep Disabled:
5) Plugged-in to the wall. High Performance Power Profile. Idling.
6) Plugged-in to the wall. High Performance Power Profile. Running Prime95 in the background on all the cores.

That should give us a good idea of what's going on. Then we can give you advice on how to approach Lenovo if it is something wrong with the machine. Anyone/everyone else is welcome to jump in to help figure out this problem.

 

Problem fixed . Apparently Thinkvantage update wasn't finding the new Bios version that was available (it would on my T61). I went on Lenovo's site and saw the version listed was 1.22 and mine was 1.16. So if anyone else is having the same problem this is the answer. Sorry to waste anyone's time, I should have made sure earlier instead of thinking update would know if there was a new version out.

 

UPDATE. Problem is not fixed but now I somewhat know what causes it. Seems like either a bios or power manager bug. Everything functions as it should only when the battery is plugged in. As soon as you take the battery out the cpu gets stuck at the lowest frequency again, plug it back in and bam works perfectly. I thought the bios update fixed everything because when you update the bios it prompts you to plug the battery in, so when I restarted the computer after the update it had the battery in it and was working. If anyone else can try this and confirm I would appreciate it, to know whether its just my computer or a widespread problem.

 

It makes sense that if you run the computer with the battery out it will throttle down.

If you have a 65w AC adapter, and you super stress the system, there is a slight chance that it may draw more than 65w, which would be bad. With a battery, the battery can provide the extra juice needed, so no throttling.

I remember reading this a number of years ago about another Thinkpad model. Why are you running the computer without the battery anyway?

 

I'm confused. Are you trying to use your T420 without the battery?

 

When I use my laptops on AC power for extended amounts of time I sometime take the battery out so it is not constantly be topped off. I do this in hopes to slow the degradation of the battery. I never had this sort of problem with my T61 and I had the battery out of it probably 50% of the time.

 

The battery maintenance options in Power Manager work very well. Pulling the battery out is unnecessary. Here's the setting I use across all of my machines now.

 

Good information to know, never heard of this and since it never came up from using my old laptop this way I never even thought about it. It does make sense though since my T61 had a 90 or 95watt power supply.

 

So if I had a 90 watt ac adapter it would run the same as having a battery plugged in?

 

They are designed to be run with the battery in. If you want to tweak performance, you have fine grained control in three areas. The BIOS, Control Panel Power Options, and Power Manager.

Lenovo's Power Manager has matured nicely. Click the Advanced mode button on it and you will see 5-6 power plans. I use the Power Source optimized plan most of the time with some personal tweaks.

I have also created a couple of custom plans. One for extreme battery conservation. The other plan is full turbo and max performance. I only use it for HD encoding.

If you modify a plan, there's a button for each to reset the plan back to default settings. That's nice. Let's you experiment wildly then reset back to the factory settings.

Import and Export works. Export and look at the .INI it creates. This will provide more insight as to what's under the covers.

 

Mine is showing what ever you all are reporting. With or without speedstep enabled the experience is the same doing normal computer work (Office applications, email, Internet browsing, and some YouTube watching). I disabled speedstep to check on the battery usage to see how much of a difference it really makes for me.

 

WEI score about the same with/without SpeedStep. However, a couple of days ago, my CPU-Z only showed one cpu not dual. Unknown why nor how to fix it at the time. I reinstalled windows using ThinkVantage and Wa-La, both cpu's were visable using CPU"-Z


SpeedStep Enabled on left Speedstep Disabled on right

 

I'm very familiar with lenovo power manager, been using it for years, that's why I was so sure that the problems wasn't a wrong setting in it. I just don't understand the reasoning behind having to have the battery in. If speedstep is disabled with the battery out the system runs at full performance so obviously it is capable of doing so on just ac power.

 

Found some info on the lenovo site about it. Definitely caused by having a 65 watt ac adapter. I always like having two anyways so that I can leave one at my desk so it looks like I'll buy a 90 watt for my second one.

 

I want to scream.

 

Yes I realize I'm strange, but little things like that bug me.