Recently I have seen multiple instances (fairly rarely, but nevertheless) of the newer Dell Latitude Ultrabooks (circa 2013\/2014 models, E7440 and E7240 specifically) throttling CPU frequencies under exceptional power conditions (such as possibly a misbehaving\u00a0AC adapter or extremely low battery condition while under load). \u00a0I haven’t confirmed the exact circumstances which lead\u00a0to this behavior, but I do know of a solution.<\/p>\n
I first noticed this when a client\u00a0recently reported sluggish\u00a0operation of his brand-new E7440 Ultrabook… which, of course, made little\u00a0sense considering the blazingly-fast parts (SSD included) that we purchased for him. \u00a0I checked the software briefly and saw no issues which would suggest configuration problems. \u00a0However, upon opening Task Manager, under the Performance tab, the CPU frequencies were reportedly below\u00a0400 MHz\u00a0permanently–which, of course, is incredibly low<\/em> considering the max Turbo Boost frequency of the i5 Haswell CPU he had of 2.8 GHz. \u00a0Fortunately, I had seen this problem once before.<\/p>\n My theory is that\u00a0it is likely related to power disruption conditions, as I have only thus far seen it happen in circumstances where an AC adapter was not providing proper voltage or where the machine was in a very low battery state while sustaining heavy CPU loads for some reason (Windows Updates, etc.). \u00a0The machine responds by throttling CPU clock rates to protect itself from possible\u00a0damage, but the problem is that it never\u00a0reverts from\u00a0this throttled state until it is powered off and the battery is removed.<\/p>\n UPDATE:\u00a0<\/strong><\/em>A new and even better solution has been found (see comments below), as some of these machines continue to suffer from the same problem even after the BIOS update has been applied. The new solution is to remove a screw underneath the keyboard, just under the “C” key (or close to it). Believe it or not, as bizarre as it sounds, this always\u00a0<\/em>works. I’ve tried it on dozens of systems at this point with success each time. Disassembly is relatively simple; check out Dell’s Service Manual for more info on this if you need it.<\/p>\n Fortunately, the solution is easy, if not a bit difficult to discover. \u00a0All\u00a0that is required is a BIOS update to the latest\u00a0firmware\u00a0available from Dell (support.dell.com<\/a>, search for your particular model). \u00a0In my most recent client’s case, an upgrade from A05 to A15 immediately corrected the problem. \u00a0It remains to be seen whether it recurs, but I do not expect it to given the last instance I saw, where we did just the same thing and the problem was permanently corrected.<\/p>\n","protected":false},"excerpt":{"rendered":" Recently I have seen multiple instances (fairly rarely, but nevertheless) of the newer Dell Latitude Ultrabooks (circa 2013\/2014 models, E7440 and E7240 specifically) throttling CPU frequencies under exceptional power conditions (such as possibly a misbehaving\u00a0AC adapter or extremely low battery … Continue reading