Latitude E6420 with Intel i7-2720QM - CPU PERFORMANCE ISSUE.

Still using A04, I see all 8 meters of Task Manager.

Someone was mentioning that the 2720QM wasn't being properly recognized by the BIOS in the newer revisions. Maybe lack of HT is a side-effect of it not being recognized (though it's odd that it would work for some people but not others)?

 

Thanks for checking Adam/Alex. I do have "All" selected in BIOS under Multi-core support. I also confirmed in msconfig boot options that all 4 cores are enabled. Before and after snapshots of CPU-Z for hyper threading setting are as below. With A05 BIOS at least the turbo boost is working. If I upgrade to A07, still the same problem with hyper threading and turbo boost does not work! Same problem reproduced in couple of more laptops in my office as well. We have reported this to Dell as well.

 

Errr... MSCONFIG, Boot tab, Advanced options... button. "Number of processors:", I see 1-8 if I try to set it.

What happens if you completely uncheck that box?

 

That's interesting. MSCONFIG was always showing only 1 to 4 options for the processors. As you suggested, I unchecked the "Number of Processors" option and restarted with hyper threading switched on.... Bang! I got all 8 threads now. Now MSCONFIG shows 1 to 8 processor options in the Boot tab. So, looks like I have to blame windows for this issue and not BIOS. Thanks!

 

Coming back to the original turbo boost issue. Anyone tried to inform dell. I opened a thread in the Dell forums:
Turbo boost disabled for Latitude E6420, bioses A06 and A07 and i7-2720QM - Laptop General Hardware Forum - Laptop - Dell Community
could you please contribute?
Any of you tried contacting dell and notifying the problem?
What is strange is that they fixed the issue for the Precision M4600 with the latest A07 BIOS, but they did not made anything for the E6420 and E6520 machines (which are quite similar)

 

Dear rossim80,

I already opened similar thread on Dell forum (Re: Latitude E6420 with Intel i7-2720QM - CPU PERFORMANCE ISSUE. - Laptop General Hardware Forum - Laptop - Dell Community) at the same time when here. However, you thread is more active so I suggest to contribute your thread.

I just called again to EU Dell support to followup my case # 655614306 and they confirmed, that bug fixed BIOS for E6420 and E6520 will be relaesed promptly. According to Dell tech support, the same issue was in E6400 BIOS and Dell already released bug fixed BIOS for it.

The best thing we can do to speed up issue resolution it to submit to Dell support this issue with link to the forum (here and Dell forum).

Best regards,
Adam

 

Dell have posted BIOS version A08 and I can confirm this version corrects the benchmark issue introduced in A06/A07. PassMark now shows a CPU mark of 7575 which is what I saw in A05.

 

I had another issue with my Dell which probably is caused by A08 BIOS.
My notebook screen started to flicker and after several minutes was black. Then, I disconnected power adapter and text on screen was visible again, however was flickering. After several minutes flickering was more intensive. I plugged power adapter again and flickering was less intensive. Then again the screen was blank and I was unable to see anything on screen. I connected external monitor and everything was displayed on external LCD correctly.
On the same day I called to Dell support and they asked me to run Dell diagnostic utility (you have to press Fn key while powering on notebook). Diagnostic utility showed: “Error Code: 2000-0415. Check LCD cable.” which confirmed the issue with screen.
On next business day Dell technician arrived and he replaced the screen. However, the same error code 2000-0415 was reported in diagnostic utility. On next day, Dell technician has come again and replaced motherboard (with A08 BIOS revision too). Unfortunately, the same error code 2000-0415 was still reported. There was no any logic explanation for this, as LCD with all connecting cables and motherboard have been replaced by Dell technician. It seems that this error is caused by a bug in BIOS A08 revision.

Can anyone confirm this?

Best regards,
Adam

 

Sorry to hear that but Dell should have tried to revert back to !06 Bios first. A07 and A08 do cause an error during diagnostic. Read

Re: E6520 Owner's Thread
Quote:
Originally Posted by CHRIS_83
I have just got the following error message in Diagnostics:

Error Code: 2000-0415

Validation: 56619

Check LCD cable

Dou get the same error warning?

Thanks!





EDIT: The error is related to the new Bios (A7 & A8) Diagnostic false positive - Lcd Cable, went back to A06 and no more error showing in Diagnostics.

More info here.

 

Thank you CHRIS_83 for this information. I will followup this issue with Dell support. I hope they will fix it in next BIOS update.

The only open question now is whether this BIOS bug causes only false positive error in diagnostic utility or maybe it can lead to real hardware failure? My screen was flickering and screen repleace was required to fix it. Is is just coincidence that my screen failed and "Error Code: 2000-0415. Check LCD cable.” was reported by diagnostic utility?

Maybe some on this forum encountered the similar issue with screen flickering?

Best regards,
Adam