High CPU Usage despite nothing showing on Task Manager or Process Explorer.
Greetings all, I hope this is the correct area to post this to, If not I apologise and could it be redirected to the correct area. Anyway, I do hope someone can help with this infuriating problem, and many thanks in advance.
I was asked to have a look at a relatively new Acer Aspire 6530g laptop recently that was beginning to become almost unusably slow all of a sudden. The system (which comes with 4gb of ram) literally can no longer run a couple of simple applications at the same time. Displaying typical behaviour of high CPU usage, ie taking a long time to respond, typed sentences seeming to pause and then jump to the end, video noticably jerky accompanied by a crackling through the speakers.
The system had a fresh re-installation of Vista done, which seemed to solve the problem briefly, reappearing again after a week or so, and then upgraded from Vista to Windows 7 in an attempt to solve the problem, again the symptoms appeared to stop after the upgrade (or weren't as evident) and returned yet again after only another week or so.
First thing i did was check task manager for something slowing the system. I suspected perhaps some malware or a trojan on the system.
This is where it gets weird. Nothing. If for instance theres just 1 browser window playing a flash game, it slows to a crawl. CPU shows 75-95% usage, yet nothing is seemingly using it. To go a little deeper I installed sysinternals process explorer to see a little deeper into what might be causing it. Again, nothing. Showing overall High CPU usage, but nothing appeared to be using all of the CPU.
Whilst something relatively intensive (playing video for instance) was happening, this process could clearly be seen using a percentage of the CPU, but nothing else seemed to being using the rest, however the CPU still showed overall usage of 90-100%.
After extensive tests on the system it came up clean every time for malware or spyware or anything of that nature hidden on the computer. I am absolutely certain the system is trojan/malware free. I tried replacing drivers with newer versions from the manufacturers website as well to seemingly no avail.
Frustrated by this I hit the internet to search for a solution. I found a number of different posts on forums by, surprise surprise, frustrated acer aspire users describing these same symptoms. But with no definate solutions offered.
The closest I've come to something that would make sense was 2 articles. Firstly this blogpost...
Which describes the ATA/IDE controllers reverting back to PIO mode instead of Ultra DMA. Which wouldnt show up on task manager but would eat up CPU. However, the description given in that article describes checking for it on windows XP. This system is now Windows 7. I've checked all the Controllers in Device manager on this system, (theres more than just Primary and secondary IDE Channels, kinda confusing) But some either show the transfer mode as Ultra DMA or don't display anything. To try the solution offered in that blogpost I uninstalled all the controllers and let windows redetect and reinstall all of them automatically, however it didnt seem to make any difference.
Secondly, i found this question on Experts-Exchange, which sounds like my prob, is unsurprisingly yet again an Acer Aspire, but which i cannot view the answer for because experts-exchange is now commercial. : \
Oh, and to rule out hardware problems, I booted the system in Ubuntu Linux from CD and visited the same Flash sites that definately caused slowdowns in windows. Everything ran very quickly, no slowdown. In fact, Flash seemed to run far too fast. So whatever it is, its in windows. But What?
If anyone can offer any assistance with this I would be most grateful, as well I suspect, will be the many acer aspire users who might find the solution here. Thanks. :)