E6400 overheating throttling

I really appreciate the help. I used to be good be with hardware but this throttling business is way beyond me. I downloaded Throttlestop and ran it, here's what it shows.



My CPU is rated for 2.26 GHz, and Throttlestop shows 2.3 GHz, so maybe it's not throttling all the time? There are certain points during the day though where it becomes unusable. I will set it up to run in the background tomorrow at work and when it throttles, it'll show in the log file.

 

Thanks John, here's the screenshot of HWMonitor.



Re: the undervolting, my laptop's still under warranty. Wouldn't it be better to get Dell to try and fix this problem? Or is it something wrong with all E6400s?

 

Like I said, many people (but not all) with the Nvidia solution, where able to fix (or amazingly improve the situation to a point that their is no visible problem) their problem by having their motherboard and heatsink replaced at the same time. If you can get Dell tech support to replace both for you simultaneously, then it would be great.

Why both together?
- When the heatsink is replace, Dell doesn't remove the old thermal past, and oil on the processors. They just add the heatsink above it all, and call it a day. This makes the situation worse.
- When Dell replaced the motherboard, again, Dell won't apply new thermal past. They will just put the old heatsink back. This will cause bad contact with the heatsink, which will make things worse.

 

CPUID HWMonitor uses the incorrect TJMax value for many of the newer 45nm Core 2 CPUs. When this value is wrong, HWMonitor will not correctly report your core temperature. Here is what the Intel specs say for a P8400.

Intel® Core?2 Duo Processor P8400 (3M Cache, 2.26 GHz, 1066 MHz FSB) with SPEC Code(s) SL3BU, SLB3Q, SLB3R, SLB4M, SLB52, SLG8Z, SLGCC, SLGCF, SLGCL, SLGCQ, SLGE2, SLGFC

TJunction 105°C

To correct HWMonitor, you will need to go into the hwmonitorw.ini configuration file and make sure the correct value is being used. This is a text file so you can edit it with Notepad/Wordpad.

CPU_0_TJMAX=105.0

The ThrottleStop log file shows a problem. When a P8400 is lightly loaded, it will be able to use some Intel Dynamic Acceleration. The default multiplier is 8.50 but when one core is in the C3/C4 sleep state, the other core is allowed to briefly use the 9.00 multiplier. The FID / multiplier being used will rapidly cycle back and forth between 8.50 and 9.00. ThrottleStop accurately reports the average multiplier being used when this is happening. That's why your log file shows FID / multiplier numbers bouncing around between 8.50 and 9.00 at the start of your test when your CPU is lightly loaded.

During your Prime95 stress test, both cores are fully loaded. This leaves you with no Intel Dynamic Acceleration so your CPU will be running both cores at the default multiplier which is 8.50. Your log file shows that even when your CPU got quite hot, it continued to run both cores at full speed with absolutely no throttling so everything was great but.......

After you reduced the load, then a couple of problems showed up. First the multiplier dropped down to 6.00 which externally slows your CPU down to 1596 MHz. It wasn't running at this low speed before you started the test. After you stopped running the test, your CPU core temperature was returning back to normal but the bios decided now was a good time to start throttling your CPU. That's a bug.

After that it also started using clock modulation throttling which is a sly way to slow down a CPU internally without notifying a user why their laptop feels so sluggish, especially when combined with the reduced multiplier. There is no reason for either throttling method to be used on your CPU let alone both at the same time. It's just a sign of a poorly designed and buggy bios.

If you were only using Prime95 during your test then you weren't even working the GPU. This throttling problem can get much worse if you try to use the CPU and GPU simultaneously such as when trying to play a modern game.

Dell's previous generation of laptop, the Latitude D830, had no problem running Prime95 + Furmark to stress the GPU at the same time without overheating or throttling. The newer Latitude E6400 with the Nvidia Quadro NVS 160M can't run that same test without severe performance throttling which may last well after the load has stopped leaving your computer feeling sluggish and unusable. Randall Cotton's 59 page Throttlegate paper clearly proved that.

For comparison, here's a half hour CPU + GPU full load test on the previous Latitude D830.

Imageshack - furprimetest.png

You can contact Dell but they will most likely give you the endless run around. The reps you talk to are not allowed to admit that there is a design flaw in many Dell laptop models built during the last two years. They don't have a bios available to fix this problem and they are too busy fixing or covering up many newer models with similar throttling issues. If you can get Dell to come out and clean your heatsink and redo your thermal paste, that might help the problem a tiny bit but that won't fix the problem in these machines that is at the bios level. Your laptop started severe throttling when the CPU temperature was fine. The problem runs much deeper than that.

 

i solved my problem by selling my e6400. Because Dell denies this problem and it could be an easy BIOS fix but they don't do it and I who knows why.

 

Fantastic. Throttlestop seemed to fix it for me. I have a month old Latitude E6410 running Win7 and every day I have had these mysterious slowdowns where everything slows down to a crawl. Running TaskManager shows that the TaskManager process on it's own would use 10-20% CPU, and other idling apps would do the same. Originally I suspected bad drivers or Win7 itself, but more research led me to believe it was overheating and then I came over this forum.

I started up Throttlestop and after toying a little with the program suddenly everything was working ok. CPU idle status went back to high nineties, and my dormant programs now take 0-2% CPU compared to previously double digit. Exited ThrottleStop and everything still works fine (CPU temperature was fine by the way). Maybe a little premature to conclude ThrottleStop fixed it, but I guess it might have taken the CPU out of a state where it was throttling everything. If so, what about a BIOS fix DELL? Will report back with my experience next time I see this problem. Usually a daily occurrence, so will probably not last long...

Anyway, to say it nicely, I am not impressed with my DELL laptop. This problem is one of 3 hardware related problems I have noticed in the short time I have used it. The wi-fi will periodically die and I need to disable/re-enable it in device manager to get it back working. If I connect an external screen without closing the lid, it will often go into a cycle showing the display for a split second on alternating screens. Probably my last DELL...

 

What CPU and GPU have you got? My E6410 with i5-540M + Intel graphics has, so far, shown no hint of any throttling problems.

John

 

we have to monitor this, i wouldn't be surprised if the e6410 is affected by this as well.

 

The E6410 shouldn't shouldn't suffer from the "overheating" of the Intel GPU because it is now sitting under the main heat sink and overall CPU / Intel GPU performance is managed by Intel to keep the combined power consumption within the design 35W ceiling. The E6410 with dedicated graphics may behave differently.

John

 

Paillote: When clock modulation throttling is being used, it slows the CPU down internally. A CPU performing at the equivalent of 200 MHz is going to have to work a lot harder than the same CPU when it is allowed to run at its full rated speed of 2000 MHz. The Task Manager percent will go up as the CPU needs to work harder.

The log file Idene sent me shows the random use of multiplier and clock modulation throttling that has nothing to do with core temperature or CPU load. That's a bug in the bios and your E6410 might have a similar bug. Does your laptop use the Intel graphics?

ThrottleStop is a low stress program so you can leave it running and minimized in your system tray without it bogging down your CPU. Turn on the log file option and just run it in monitoring mode so the next time you experience a slow down, you will have a full record of exactly what happened. It keeps the multiplier throttling separate from the two main types of clock modulation throttling and will also track your CPU core temperature to make sure that is not the cause of the problem. It usually isn't. If you're not sure how to interpret the data in the log file then send it my way and I'll have a look at it or upload it to MediaFire and post a link here.