Odd startup (mis)behavior of my new SP2

[jrapdx]

My 4300u SP2 (256GB) has been showing odd power management (mis)behaviors after shutdown and subseqent startup. This machine (lot 1352, 4300u) was not affected by the December 10 FW issue, and has not yet received the Jan 2014 firmware update.

What I've noticed is that after shutting down the SP2, and from the off state powering it up again, under minimal load the CPU utilization is 25% or 33% depending on power setting. (Power saver/Balanced vs. High performance.) If left running at this abnormally high rate, the tablet begins to heat up after 15 to 30 minutes.

If I trigger sleep (with power button, or menu), and then wake up the CPU, usage falls to near 0%. Length of the sleep interval doesn't matter, the effect is the same.

Also, when processor utilization falls to 0%, the CPU speed continues to hover around 2 GHz for at least a few minutes, even if the Power saver option is in effect. However, the CPU speed does eventually slow down to its "low power" level, ~ 0.75 GHz.

My SP2 shows such behaviors consistently, if not quite every cycle. There was no difference regardless of battery vs. AC-power, power option setting or any other setting changes I tried. (Note that the issue doesn't arise with a "restart" operation vs. powering down completely and then powering up again.)

To reproduce the problem, close all apps, set Power Option to Power Saver, choose shutdown from the menu. Let the computer remain off for >= 15 sec. Then power up, log in, go to task manager performance tab/CPU data. The utilization will be ~25/33%, and CPU speed ~2.0 GHz. Activating sleep mode and then waking from sleep will show CPU at or near 0%. CPU speed should fall to 0.75 GHz after several minutes.

The "revved" CPU issue may not be particularly obvious, but conceivably could be contributing to suboptimal battery life on SP2's. Fortunately, if it's known to be occurring, working around the problem isn't too difficult.

If anyone tries to replicate this SP2 behavior, I'd sure appreciate learning about the outcome whichever way it turns out. And if anyone knows what's going on, I would very much like to understand it.

Thanks.

 

[Rvacha]

Serious question - how do you know you aren't affected by the December firmware update? Even people (like myself) that had "successful" installs are having issues.

Do you have an SD device plugged in? If so what you describe sounds like a known bug, namely high CPU when powering up with an SD memory device plugged in. There was a post on the MS site yesterday from somebody that claims this weekend's firmware update hasn't fixed it - but it is just one report

 

[jrapdx]

Serious question - how do you know you aren't affected by the December firmware update? Even people (like myself) that had "successful" installs are having issues.

Do you have an SD device plugged in? If so what you describe sounds like a known bug, namely high CPU when powering up with an SD memory device plugged in. There was a post on the MS site yesterday from somebody that claims this weekend's firmware update hasn't fixed it - but it is just one report

Thanks for your reply. I know this SP2 was unaffected by the Dec 10 FW because the SP2 I bought mid-December was hit by it, behaving erratically after installing it. I exchanged that unit for an SP2 that was manufactured after the FW incident. The update history shows no FW downloads except Oct 24 2013, AFAIK not assoc with the problems like those following the Dec 10 FW. I have not yet received the recent FW update.

I think you are right about the SD card. I'd forgotten about having a card inserted. With the slot clear, the CPU behavior is normal. Guess I still have a lot to learn about the SP2, so many quirks to know about. Thanks for the info.

 

[benjitek]

About that SD card bug... Does that just occur if you do a complete reboot with the card inserted, or does it happen if you wake from sleep with the card in? Curious as I just ordered a 64gb card for my SP2...

 

[mennogreg]

I have had a micro SD card inserted since day 1 and have not had any CPU issues. I mostly use sleep/hibernate, so perhaps I just didn't notice on cold starts. I have only games installed on the card though, maybe its an indexing issue if its other kinds of files.

 

[jrapdx]

Yes, the CPU issue shows up with a full shutdown and subsequent boot up, when the SD card is in the slot at startup. AFAICT the CPU has not shown the behavior following a "Restart" or on waking from sleep or hibernation.

I have a 32GB mSD card. Inserting into a running system has no effect on the CPU utilization or speed. But if in the slot when the SP2 boots up, the CPU effect is evident.

(Maybe somebody has tested it, but seems not real likely that card contents would affect the problem. Interesting idea though, e.g., if the kind of file system would matter, etc. So many variables, so little time...)

So kind of a pain to remove and reinsert on each boot up. My work around has been to leave the card in the slot, and after booting, check the CPU status with taskmgr, and if "revved" put into sleep mode and immediate awaken. The CPU activity then falls to normal level. For me, that's somewhat less trouble than keeping track of the tiny card. You just know I'd lose it somewhere along the way.

One more wrinkle, I'm not sure if the "fast startup" setting has any effect on the CPU activity on boot up. Seems that sometimes when set "on" the CPU activity was normal on boot up, but I haven't yet really tested this.

 

[mennogreg]

Perhaps the speed of the card plays a role? I'm using a Samsung 64GB Pro on mine, one of the faster cards available, though I initially used a 32GB PNY 40MB read card and don't remember experiencing it either. What programs are running at startup on yours?

 

[jrapdx]

Perhaps the speed of the card plays a role? I'm using a Samsung 64GB Pro on mine, one of the faster cards available, though I initially used a 32GB PNY 40MB read card and don't remember experiencing it either. What programs are running at startup on yours?

The mSD card is a 32 GB "Lexar High-Speed Class 10". I thought it would be adequate for backup purposes. Currently it contains 2.7 GB of text, source code, photo images, configuration files and some executables from my former SP2. However, I'm not running programs from the card, the runnable files were just stored there and copied to the SSD for use. Running programs from the card was generally unsatisfactory as it's quite a bit slower than running from the SSD. No surprise there.

Curious about your 64GB card. Do you run programs from it? How much difference vs. running from the SSD?

So far, startup is pretty much just the defaults. I've added a few drivers (e.g., Wacom ISD driver), but that's it. Of course I do intend to do a lot more with the SP2, using Hyper-V for one, but it's not activated just yet. According to taskmgr, currently 39 processes are running which I think is pretty close to the minimum.

BTW, I'm in the habit of making sure the SP2 is fully off before putting it in my brief case. After my original SP2 was damaged by the Dec10FW, it would come on spontaneously from sleep/hibernated state. Rather spooky. I was concerned about potential hazards if the computer "woke up" in transport. I feel more secure if it's unambiguously shut down when I'm not using it.

 

[mennogreg]

I run games off of it (the games are installed on the card), though they're older games which have low bandwidth requirements; the "newest" one on it is Neverwinter Nights 2. While I don't doubt the SSD would be even faster, its a 70Mb/sec Read card, and I've never experienced any significant slowdowns or load times (takes a little longer to install the games on it, as it only has 20Mb/sec Write capability.)

Your startup is leaner than mine, and I usually have about 50+ processes running on a cold boot. Have you tried removing files from the card to see if there's a change? A class 10 card means, if I recall, that it have a minimum of 10Mb/sec Read/Write, which may be fine for your usage, but if Windows is scanning the files on it (or Windows Defender is scanning EXE's?) it may be just a bottleneck to cause what you're experiencing?

 

[jrapdx]

I run games off of it (the games are installed on the card), though they're older games which have low bandwidth requirements; the "newest" one on it is Neverwinter Nights 2. While I don't doubt the SSD would be even faster, its a 70Mb/sec Read card, and I've never experienced any significant slowdowns or load times (takes a little longer to install the games on it, as it only has 20Mb/sec Write capability.)

I've never been too sure how accurate the transfer rate claims are, and of course, I don't have a convenient way to test or verify how fast the card is, or what conditions affect transfer speeds. It does make sense that reading is faster than writing. In any case, I'm pretty sure your SD card outclasses mine by a considerable margin.

Your startup is leaner than mine, and I usually have about 50+ processes running on a cold boot. Have you tried removing files from the card to see if there's a change?

Since the SP2 is new, I've deliberately kept it lean, not only to make sure it's working properly, but also to make it easier to off-load things if I'd have to return it. So far, it's working OK, and I expect I'll start to really use it pretty soon. Down the road there will no doubt be a lot more running at startup than there is now.

A class 10 card means, if I recall, that it have a minimum of 10Mb/sec Read/Write, which may be fine for your usage, but if Windows is scanning the files on it (or Windows Defender is scanning EXE's?) it may be just a bottleneck to cause what you're experiencing?

I don't think the files on the card are making any difference in performance. For one thing, the startup issues only involve the CPU activity, and once that is "normalized" the system runs the same as though no card was in the slot at startup. For example, the number of processes is the same, and so on. Also, inserting the card after startup doesn't change anything either.

None of the exe files on the card are in the runtime path, so I don't think the OS is checking them, or even "knows" about them. These files are just stored, not installed there. My speculation is the problematic startup behavior is just a weird firmware bug, having something to do with the bootup sequence. The mere presence of the mSD card in the slot somehow triggers an "interrupt storm" and high CPU utilization, while at that point the contents of the card are irrelevant.

The mSD card I'm using was bottom rung cheap, and didn't come with any transfer specs other than "Class 10", so I assume it's not too swift. Most likely, I'd have to spend more than $0.75/GB to get the best results.

 

[Rvacha]

jrapdx - From what I've read I'd say you've hit the nail on the head