Throttling When Plugged in to ACEdit

UPDATE: One user on NotebookReview who previously experienced consistently reproducible severe GPU throttling (down to 135 MHz) has reported that the issue appears to be solved with the A03 BIOS update. Now his GPU will occasionally drop out of turbo mode down to 941 MHz, but it will maintain that clock speed. Conversely, his CPU, which prior to the BIOS update would always run in Turbo mode even under heavy load, now throttles slightly (gradually down to 1600 MHz, likely to increase available cooling capacity for the GPU), but the net effect is that games run much better.

There have been a handful of users who have been frustrated by a loss of performance (sometimes sleight, sometimes drastic) under load, such as that put on the system by a demanding PC game.  Bokeh, an owner of a pre-production M3800, claims that he has tried to induce throttling on a pre-production M3800 and it does not happen unless airflow is intentionally obstructed; other users have reinforced this claim, indicating that the XPS 15 and the M3800 are designed to be able to fully use the hardware contained within them so long as they have access to fresh air.  One user specifically noted that >90°C CPU temps trigger throttling on the XPS 15.

Things to consider if this is happening to you:

  1. Check the ability of your laptop to manage its heat.  Are the fans running without a problem?  Are the vents in or out of the laptop blocked by anything? 
  2. Are you running current drivers for the GPU?  Even if you are, it may be worthwhile to re-install.
  3. Are you expecting too much out of your system?  The GT-750M is a mid-tier GPU.  Consider reading this thread on NotebookReview, in which users comment that the low-voltage CPU in the XPS 15 combined with the limits inherent to the GT-750M GPU mean that the XPS 15 should not be considered as a gaming rig, though it is certainly capable of some gaming.  In general, they suggest you keep gaming resolutions moderate (at or below 900p) and eliminate any graphic effects that you don't have a dying need to see during gaming.  NotebookCheck, in this report, claims that the GT-750 with 2GB DDR5 RAM (such as it is configured in the XPS 15) is a reasonably capable card, however, and you should be able to play at least some games at 1080p.  Experiment to find the sweet spot for your particular game of choice.

To document any throttling that may be going on, you may wish to follow these instructions (originally posted by [-Mac-] to the user forum at NotebookReview on 20 November 2013:

Instructions [for using HWinfo64 while playing games to record system information]:

1) Download HWinfo64: portable version (this version does not need to installation)

2) Launch your game, and come back to windows then you can launch HWinfo (remember to set logging mode), in this way GT750m will be logged

3)Come back to your game and play normally

4)Send CVD file in this forum, if CVS file is to big or file extensions is not allowed you can use 7Zip, Winzip or Winrar.

This file will record all information such as the clock of GPU and CPU their load and their temperature throughout the time that you have played.