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SciBee

Why some tabs are slow and laggy and others are not

74 posts in this topic

Since I received my V3 tab I was always wondering why it was sometimes slower than my V1 and partially laggy.

As my family is in the country today I had some time for research :D

First I configured Trickster Mod to run the tab at frequencies between 504MHz and 1992MHz.

This removed the lags while scrolling in a browser - 96MHz is too slow.

Then I tried to check if the upper limit also was properly applied by running CPUTemp and Antutu simultaneously.

Antutu was running in the background and this is what CPUTemp logged:

post-177-0-74414400-1401568882_thumb.png

You can clearly see that the CPU clock was limited to 1104MHz while the CPU was running at full load and at temperatures >60°C (the middle area).

It is also obvious that the CPU sometimes runs at 1992MHz while there is no maximum load and lower temperatures.

While the test was running I could see "jumps" of 10°C within seconds!

I thought the CPU driver was reading the clock settings at boot time and storing them in it's environment.

So I created a new boot.img with "scaling_max_freq" set to 1992000 and "scaling_min_freq" set to 504000 like Cural did and flashed it via TWRP.

But the results were almoust the same. After some more tests the CPU temperature reached a maximum of 73°C! But the back was still feeling "normally" warm.

At this point I recognized that something must be physically wrong with the CPU cooling and I opened the tab.

This is what I found - the back is upright behind the electronics to show what belongs where:

post-177-0-45955700-1401569247_thumb.jpg

First I did not trust my eyes as I already had opened my V1 and checked the CPU thermal interface pad there.

Then I realized that Onda has left the CPU cooling away at all! And this was not done by mistake because you can clearly see that the corresponding cutout in the yellow isolating foil on the back is missing.

I must say, I feel a little betrayed by Onda.

After thinking a while I must say that this is a big bunch of shit!

After calming down I took a carpet knife and cutted the foil to meet size and position of the CPU +10% and I applied some special thermal grease to the CPU.

I used T630 (Ebay link) which is quite soft and easily applicable. It's like a soft chewing gum and does not cause the mess in the device that normal thermal grease does while flowing all around where you don't want it to.

Here's a pic how that looked like before I reassembled the back:

post-177-0-19481100-1401569920_thumb.jpg

After reassembling I ran the same tests again using my modded boot image, CPUTemp and Antutu.

Here is the result:

post-177-0-77883200-1401570552_thumb.png

Now the CPU temperature maximum was 57°C instead of 73°C and the tab was running at higer speeds than before. Antutu increased too (7000 points in my case).

It is quite difficult to further improve the CPU cooling because if you slightly press on the CPU the PCB is moving towards the display. It seems impossible to increasy the applied pressure to the thermal solution. And the efficiency of thermal interface materials depends on the applied pressure!

 

Well all this tells us several things:

  1. Abandon all hope that Onda will ever make any efforts to get the most possible gain out of this tab as they made it worse for the NEW V3 tab. The V1 tab HAD a CPU cooling pad.
  2. It seems that Onda hardcoded a limit of - I guess - 55°C into the CPU governor. If the CPU temperature rises above that value "scaling_max_freq" is dynamically rewritten with lower values and the speed steps down. I checked that in realtime over ADB. And I think it's hardcoded because I could not find the config parameters. Neither in boot nor in system.
    I could not find a full specification of the M802, but I can't imagine that 55°C is it's DIE temperature limit.
    It is very likely that Onda mixed up the maximum operating temperature (the surrounding air) and the maximum DIE temperature (inside the CPU).
  3. The V1 did not show this problem because:
    1. The V1 has a CPU cooling pad.
    2. The V1 seems to not support reading the CPU temperature at all. The dignosis tools that showed the temperature on the V3 did always show 30°C at the V1.
  4. All tests were run on Rozak's ONDA_V975m_V3_v2.0.1_rozak_20140515-4G version. Users reported (e.g. eteles) that their tabs were running faster on Rozak's V2.0.1 beta version.
    I'm quite sure that onda modified the temperature limit in the governor between these two versions because the knew that they would run into problems omitting any form of CPU cooling.

BTW: After all mods my old cracky repaired V1 is still faster than the new V3 :(

 

I have no idea how the V4 looks concerning the CPU cooling as I've never seen one open.

Maybe one of the V4 owners dares to open it. Don't hesitate - it's easy!

 

I also suggest all users to check their CPU temperature. It's quite simple:

Install Antutu and CPUTemp. Both are free.

Run CPUTemp and open the "Changing Curve". Switch to your homescreen and start Antutu. Start the test.

Change the task back to CPUTemp while Antutu is testing in the background and watch the curves...

Then - either :D  or :angry:

 

 

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got a V4 and did the test :)

 

The temp didn't get higher than 56,5

 

Settings same as you mentioned with Trickster.

But the AnTuTu results is that the V4 dropped to 21,024 from 27,300 before with these cpu settings :(

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Oh man, why are you so unlucky?

I feel sorry for you... I have a v3 and I have a cooling pad where it should be.

On the other hand, my tablet doesn't support temp readings...

Here are the results after running Antutu X

8y2edumy.jpg

Cpu temp always stays at 30°C

Tablet feels warmer, but it doesnt know that, so I can always have 1,9Ghz

I guess that's why it sometimes 'freezes', with random stuff on the screen and weird noises from the speakers :P

Edit: Ofc I have boot.img modded, 408-1992Mhz

Wysłane z mojego ONDA A9 Core4 przy użyciu Tapatalka

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I am experiencing the same thing as you SciBee, and had come to the same conclusion.

This is the first documented evidence of the problem, though, as well as the solution, so thank you soooooo very much for taking the time to do a write-up on this. We need more people like you working on this tab.

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@skippie:

Obviously your CPU is in good contact with the cooler. So you can lean back and be happy.

The V4 (at least one of them) seems to have a cooling pad.

Regarding the Antutu results: If CPUTemp was running in the foreground this is quite normal as it consumes CPU cycles then.

If Antutu was the only running task then simply revert the CPU settings by disabling or uninstalling Trickster Mod - you will be back to the default settings then.

 

@Cural:

Unfortunately the V3s differ from each other. Your V3 looks more like a V1 but with bluetooth :confused:

I think - as your tab seems unstable sometimes - that your cooling pad has no or bad contact to the back.

If you will ever open your tab again take a close look at the imprint of your CPU onto the cooling pad or put a very thin layer of normal heat grease on your CPU, close and reopen the tab and see how much grease was transferred from the CPU to the pad.

If you are unsure about the contact I suggest to revert the 1992MHz mod or you might broil your CPU one day as all safety is gone because your system can't read the CPU temperature.

 

@PityOnU:

Thank you very much. I also appreciate your efforts to make the infos and rumors spreading all around provable and reliable.

I suggest to copy my solution to your tab.

 

@Arqtico:

Your CPU obviously has no cooling pad or CPU, pad and back are not in contact with each other because the peak temperature of your CPU was @75°C!

As you are running 1.1.0 oficial rom it also seems that your governor does not react to the CPU temperature.

This way your tab is fast, but not reliable and might become unstable - even your CPU might be boiled one day if you run an application that puts longer stress on your system than Antutu does.

If you should move to V2.0.1 release I'm quite sure that your tab will significantly slow down.

I suggest to open your pad and check the thermal solution!

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These are great news!

Thanks to Scibee for making these tests and give us insight.

In which Antutu did you get the extra 7000 points and what was the score?

 

I have a v3 with custom 1.10 rom and I wonder if there is any way to unlock permanently the 1992 freq.

Except if the only thing needed is to keep temps down, in order to avoid thermal throttling.

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These are great news!

Thanks to Scibee for making these tests and give us insight.

In which Antutu did you get the extra 7000 points and what was the score?

 

I have a v3 with custom 1.10 rom and I wonder if there is any way to unlock permanently the 1992 freq.

Except if the only thing needed is to keep temps down, in order to avoid thermal throttling.

 

Cural explains it very well

 

You can change it without flashing anything by using Trickster MOD after remounting rootfs as r/w.

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Cural explains it very well

 

You can change it without flashing anything by using Trickster MOD after remounting rootfs as r/w.

I Installed trickster but it gives me till 1608mhz.

I guess this doesn't work with 4.3 Roms?

 

Also, my temp during running of Antutu got a max of 57 degrees.

Does this mean that I have cooling pad?

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Also, my temp during running of Antutu got a max of 57 degrees.

You most likely have one and it seems to be in contact. Be happy...

I never tried TM in 4.3 ROMs.

In the settings activate "Kernel Settings", "SysCtl Editor" and "Notification".

On the "General" page set "Min" and "Max" frequencies.

Then switch "Frequency Lock" to "ON".

Then click to the apply hook in the top bar next to the settings button.

Reboot

Wait until TM reports that the settings were applied.

This of course will only work if your tab is rooted!

 

The frequency in the "Max" field is dynamically updated by the governor IF it reacts on temperature rises.

So if you open TM the next time you might find different values there. But I only saw this on 2.0.1 release until now.

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I Installed trickster but it gives me till 1608mhz.

I guess this doesn't work with 4.3 Roms?

 

Also, my temp during running of Antutu got a max of 57 degrees.

Does this mean that I have cooling pad?

TM never worked for me on 4.3, that's why I went with editing boot.img

On 4.4 it sometimes works, sometimes not, but I still use "my" method ;)

 

@SciBee

I've opened my tab several times, the pad is not placed correctly.

I'm going to simply exchange it for one of better quality and place it properly, but it will take a while, I've got a few things on my mind now (finals mostly).

 

Edit:

SciBee - I wouldn't be suprised if this was v1 with just added BT :P

I ordered v1 (there was no v3 then).

I've waited over a month for seller to even ship it.

He said they were waiting for new delivery - shipped, I've received 'v3'

What a mess... :P

Edited by Cural
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I am getting same results as Cural,my CPU temp is always at 30°C.My cpu is running at 1608.

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I opened mine yesterday, it's a V3 and it has a thermal pad. I actually opened the tab for another reason (having trouble with the charging cable staying in charging position even after cutting some of the plastic. Problem solved when I cut the plastic on a Samsung phone micro usb cable. It's charging properly now.)

Sent from my ONDA A9 Core4 using Tapatalk

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Could you show your tested way of opening the tab? (pictures and/or video)

 

I have v3, run the Antutu test while looking at CPU temp.

 

A few observations

 

1) When the Antutu test is not in the foreground, it does not properly test your tablet, so whatever score it shows there seems kinda unreliable.

 

First I ran the test with CPU temp on foreground but when the GPU tests kicked it I allowed it to use the screen and my test was 27.000

Then I kept putting the CPU TEMp on foreground and got just 17.000 the first time and 21.000 the second.

 

So, the CPU is not pushed correctly if ANtutu runs in the background

 

2) My tablet with official 4.4.2 ROM does not read CPU temp, it was stuck at 30C

 

3) the highest cpu freq it reached was 1992mhz but only momentarily and just 2-3 times, mostly 1608mhz when running at 100%

 

I have bought one V1 v975m and two V3 (I sold the latter one). The fastest of them all was the second v3 tablet I received, to the point where I actually regretted selling it. With my current tab ROM v1.0.9 was DEADLY slow...the same ROM with the second v3 tab and even all the chiniese shit in was just flying...

First bought from Geekbuying, second from Pandawill, third from Aliexpress.

That same tablet was the only one which was actually unopened/sealed...it also included ear plugs and OTG cable...I guess the other stores remove those "candies"...

 

when I read the initial post I thought that what would establish you got a "too cool for cooling" tablet was to run the test and check your cpu frequency, i.e. if it is consistently below 100%.

 

So, do I conclude that my tablet could be running with no general lags because of a lack of CPU temperature reading? And the presence of any cooling or not cannot thus be established unless I open the backplate?

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How to open:

 

I bought 3 v3's on Aliexpress, only mine has the issue (freeze/overheat), but rarely.

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Regarding the opening procedure:

There are plenty of videos out there showing how to open an iPod for battery exchange. The V975M is opened exactly the same way. Use your fingernails to lift one corner a little bit. Then insert a small plastic tool like a guitar pick (the ipod tool is perfect) and move it all around - if you have done it once you will see that it's really easy. Takes less than a minute...

  1. Your Antutu results are ok. I did not primariliy use Antutu to test the tab's performance. I just wanted to use a free tool everybody knows to put heavy load on the CPU.
  2. A V3 in the serial number seems to only say that there is bluetooth onboard. Obviously there are great differences between the V3s out there.
    If your V3 does not report the CPU temp you can never be sure that the CPU is cooled at all. It might look like mine inside.
  3. This is typical for a unmodified boot.img or Trickster Mod not installed (you can't, as you are on unrooted stock ROM). Onda uses some sort of trick that rises the clock to 1992MHz some times but only while running Antutu. That way they could advertise with a speed the tab does not support in reality running any other application. One could think of betrayal - of course not me ;)

Your conclusion is correct. You might broil your CPU one day IF there is no cooling pad. And, as you can't read the CPU temperature, there is no other way to check this but opening the tab. :(

 

Edit: lol.

Cural, saw your perfect video right after posting this. Great man...

But I'm afraid, you have to open it again. I might be wrong, but it looks like the yellow isolating foil is continued behind the cooling pad.

If yes, you should also make a cut out and stick the pad directly to the aluminum. The way it is mounted now there is a big thermal resistance between the pad and the back - the foil.

Edited by SciBee
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Yup, you're right, there is a foil between pad and case.

Update - was :P

 

161m0wy.jpg

2mqnnlv.jpg

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@SciBee

 

1) my remark was meant to show that when Antutu is NOT on the foreground, then it does not really seem to stress the cpu properly, i.e. one might not see rise in temperature or full rise in frequency and this would be attributable to the test running in the background.

 

so it seems to me.

 

2) Yep

3) I got it rooted but have not tried any script or mod outhere. Probably will at some point.

 

Thanks for pointing to this fact, so we can rectify the potential issue.

 

 

@Cural

 

awesome video, thanks!

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You most likely have one and it seems to be in contact. Be happy...

I never tried TM in 4.3 ROMs.

In the settings activate "Kernel Settings", "SysCtl Editor" and "Notification".

On the "General" page set "Min" and "Max" frequencies.

Then switch "Frequency Lock" to "ON".

Then click to the apply hook in the top bar next to the settings button.

Reboot

Wait until TM reports that the settings were applied.

This of course will only work if your tab is rooted!

 

The frequency in the "Max" field is dynamically updated by the governor IF it reacts on temperature rises.

So if you open TM the next time you might find different values there. But I only saw this on 2.0.1 release until now.

So I made test with TM and selected 312-1512.

Settings were active after reboot, but my temperature reached during Antutu 77 degrees!!

Why so big difference in comparison to normal 96-1608?

 

And also still no selection for 1992.

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I've measured my cpu

19mmx19mm, so buy 20x20 one (it is a common size)

I'm not sure about thickness of the pad, but I would go for 1,5mm.

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Why in my own tablet v3 2.0.1 rozak rom the CPUTemp show 30 degrees celcious?

What can I do in order to fix it? Or is it impossible to do something?

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Oh man, why are you so unlucky?

I feel sorry for you... I have a v3 and I have a cooling pad where it should be.

On the other hand, my tablet doesn't support temp readings...

Here are the results after running Antutu X

8y2edumy.jpg

Cpu temp always stays at 30°C

Tablet feels warmer, but it doesnt know that, so I can always have 1,9Ghz

I guess that's why it sometimes 'freezes', with random stuff on the screen and weird noises from the speakers :P

Edit: Ofc I have boot.img modded, 408-1992Mhz

Wysłane z mojego ONDA A9 Core4 przy użyciu Tapatalka

I don't know if I have cooling pad or not. ( will checkout later this evening) . What I found :

 

temperature keeps 31C

majority of atutu time is a 1600mhz cpu freq 1,992 has been used for few sec. and the beginning without visible temp. impact

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Here is my V4 running stock 1.1.0

 

post-2198-0-13503300-1401753837_thumb.jp

 

As you can see, it has a pad (are we sure it's thermal?), it is stuck directly onto the yellow insulator, it is aslo 2-3mm offset from where it should be so misses true contact with the cpu.

 

I cut a gap in insulating film in the correct position and re-applied but as you can see from the CPU temps, it still runs hot, hence my wondering if the pad is thermal or if it's just to cushion the cpu from impact. I will be buying a thermal pad to make sure.

 

post-2198-0-75313100-1401753866_thumb.pn

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Strange. I have cooling pad right now connected with a back of my tab. Ive locked my cpu freq beetwen 916 and 19200. Running stress test with havy load for cpu. Cpu tempplus shows high usage of max freq but temp still keeps on 31C .I can feel slight temperature diference at the back of tab this is still not reflcted in the cpu temp measurment. Should it be like that?

Wysłane z mojego ONDA A9 Core4 przy użyciu Tapatalka

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