Dell E6400/6500 (overheating, lock up, CPU 100%, slow) due to downclocking/down throttling
Posted by mikeg on February 10, 2010
Purchased E6400 (2.8 CPU, 4GB RAM, NVIDIA Quadro NVS 160M) early 2009, did a clean install of Windows XP 64 bit and had a rather pleasant 8-9 months: have a docking station (E series) with two monitors at home and at work and didn’t have any issues with the machine.
In October 2009 after playing with Windows 7 inside VMs and on my home PC, decided to upgrade my laptop (Win 7 64 bit). Even purchased SSD for the occasion :). Installation went great and first impressions were very positive. Everything ran great and fast (and I run a lot of software at the same time) until I put the laptop into the docking station. After 5-10 minutes of any moderate activity my computer would lock up: Task Manager would show 100% utilization but not pointing to any specific process. Hard rebooting and taking it out of the docking station seemed to eliminate the issue. After a few failed attempts to resolve the issue (including having Dell replace the docking station, updating bios and all the drivers, etc), I gave up using the docking station and was successfully using my laptop without any performance issues until mid-January. In mid-January similar lock up issues started happening again. Because it started happening outside of the dock I thought that Windows 7/drivers are at fault and opened a case with Microsoft. They had me run some tests, do a few memory dumps and suggested that the issue is caused by the video card driver and that I should uninstall and just use the one that came with Windows 7. Followed their directions but that didn’t help. At that point I decided to take the plunge and do a full reinstall hoping that clean install + latest drivers will eliminate the issue.
Last weekend I updated the bios to the latest A20, did a clean install of Windows 7 64 bit and all the drivers available on Dell’s site. Came in on Monday hoping to finally be able to use my two monitors but after 10 minutes in the docking station the same problem occurred. Very frustrated and starting to go a bit nuts, I asked our IT guy to contact Dell and demand a replacement unit. He did something better than contacting Dell (which is becoming a very frustrating experience): he found a forum post that described the problem I’ve been experiencing and proposed a few solutions. His google-foo was better than mine because there is a discussion on Dell’s forum going back to 2008 with people having this problem and I didn’t find it in October.
You should read this post as it provides a LOT of detail of why this is happening and suggestions on how Dell should address it.
Quick overview: laptop overheats and that throttles down the CPU, making a 2.8 machine run at 700 or lower which causes 100% utilization and all the symptoms that I experienced. On my laptop it seems that the GPU (video card) is the one causing the issue: it constantly runs at about 55 C, but as soon I put it into the docking station temperature jumps to 70+ C and that is when all the fun starts.
It is amazing that after 16 pages of people documenting their issues related to this and Dell releasing at least 6 BIOS updates since the first report, this issues is still not resolved – according to workarounds people found, it seems like a flaw in the code that determines when the throttling should start.
What is not fully clear to me is why I didn’t experience this with Windows XP. I even opened the case to see if there is a lot of dust which might explain why I started experiencing this 9 months into using the machine, but the case was clean.
Here are ways to deal with this:
- contact dell and have them replace the heat sink and have some high quality thermal paste instead of what they use (this worked for some people, but not for others)
- put a “laptop fan” under the laptop – this worked for me (at least for one full working day)
- there are utilities (RMClock) that allow you to control/disable downclocking (see here for steps), but there are some issues with running them on 64 bit version of Window 7 due to driver signing requirement. People have workarounds posted
- SpeedFan is very useful for monitoring internal temperature of the CPUs/GPU and clock speed
I found this excerpt from tinkerdude’s post very accurately describe my situation over the last few months – I knew there was a problem, but didn’t know what was causing it.
The reason there aren’t more complaints (though many are accumulating these days) is that users who experience this problem simply have no way of knowing what the cause is and are likely to blame the wrong thing (Windows, recently installed software, cooling hardware, etc.). Untold masses may be adversely affected by this problem, but nearly all of them wouldn’t know it because there’s no way for them to tell. Also, the problem is at its worst only when in a docked configuration, which may not be common.