Alienware 18 CPU Throttling

In my case, the system goes from 45-50 degrees C while idling to 85 degrees C under load (running 3dMark, hottest during the last test, of course.) with Processor Current Limit set at 55.000A

And the same temperature range give or take a degree C while running XTU's built in CPU benchmark.

Changing Processor Current Limit to 95.000A gives me temperature ranges between 48-50 degrees C while idling and up to 90 degrees while running the XTU benchmark.

The fans seem to throttle up enough to lower the temperature to about 70 degrees whenever it has spiked during the hardest part of the benchmark though.

The average temperature during the XTU benchmark is 67 degrees at 55.000A and 69 degrees at 95.000A.

Hope those numbers are of some use to you :)

Chris,

Check out this Review from NOTEBOOKCHECK
http://www.notebookcheck.net/Review-Alienware-18-Notebook.102566.0.html

Here's the interesting part:

Turbo Boost
Unfortunately, our review unit cannot use its full Turbo Boost potential. While the CPU worked with 3.1-4.0 GHz in single-core benchmarks, it only ran with 3.2 GHz in multi-core benchmarks. This result is sobering and not even close to the alleged potential of the Core i7-4930MX. It could reach up to 3.7 GHz in theory; 3.2 GHz are comparable to a Core i7-4700MQ. If you spend that much money for a processor, you can expect the corresponding performance or the CPU upgrade makes no sense. We will have to wait and see if Alienware fixes this issue; some benchmark results show a negative impact of the limited Turbo Boost. 

Single Core Rendering

Multi-core rendering

 

CPU and GPU Load

 

Dell-Chris M, recreating the problem in  my case is very straightforward:

1 - buy an Alienware Haswell-based system, in my case the AW 18 with 4900MQ

2 - do anything with it that puts a load on the CPU (gaming, video encoding)

3 - use whatever tool you want to see the CPU multipliers throttle way back, usually to around 3.1 Ghz but sometimes as low as 2.8 (actually UNDERclocking!)

Using Intel XTU and/or Throttlestop, Windows users have a functional workaround to at least get the Intel-rated turbo speeds out of our processors but forget about tweaking beyond that since the fan tables are messed up and the CPU quickly goes into thermal shutdown much past the rated turbo speed.  What we need is all these options in the actual BIOS so the system performs as expected out of the box.

Just got my Alienware 18 4900MQ and I am getting  by the minute. On load it never goes over 3.1Ghz. I will return it 10 days if there is no bios update.

Well I tried everything, can't do nothing for Linux.

Sure XTU works ok when in windows but I use Linux so bye bye Alienware.

Nice machine.

I have escalated all of your comments as well as the thread on NRF. Our engineers are discussing what we can do. This will take time.

Thanks Dell-Chris M, the vast majority really love their machines and just want a proper solution to this throttling issue.  I'll be happy to provide more details if needed.

Ok I did some tests and this might be interesting.

If I switch to the onboard Intel graphics then everything looks good!

The "Power Current Limit" seems to be 95A which is good.

If I switch back to the nvidia setup then the "Power Current Limit" becomes 55A and the CPU never goes over 3.1Ghz when ALL cores are 100%.

Thanks all! I have gathered your recent notes and sent them to the team.

Ok, so people who uses Linux like me.

I found a temporary solution until BIOS is fixed.

The Power Current Limit register is 0x601.

Solution

Use msr-tools and kernel module msr.

On the 4900MQ:

rdmsr 0x601

0x101414000001b8

Only the first (16-bits) is interesting.

So, 0x01b8. Now The first 3-bits are for something else (I won't go in details here).

So, 0x01b8 shifted 3-bits = 0x37 = 55 (55A)

To set your own current (i.e. 95A):

wrmsr 0x601 0x101414000002F8

This will set the power current limit to 95A.

Epic Linux workaround, bravo!

I use my alienware for work and my work requires lots of processing.

This machine is incredible for what it is (with the fix of course).

However, the fans algorithm need to be tweaked. Temperatures are erratic when pushed, sometimes they kick in too late.

Temps are usually ok, but they sometime peak mid-90s.

Ok, so people who uses Linux like me.   I found a temporary solution until BIOS is fixed.   The Power Current Limit register is 0x601. Solution Use msr-tools and kernel module msr.   On the 4900MQ:   rdmsr 0x601   0x101414000001b8   Only the first (16-bits) is interesting.   So, 0x01b8. Now The first 3-bits are for something else (I won't go in details here).   So, 0x01b8 shifted 3-bits = 0x37 = 55 (55A)   To set your own current (i.e. 95A):   wrmsr 0x601 0x101414000002F8   This will set the power current limit to 95A.

I realize you are using this technique as an alternative since XTU and ThrottleStop do not work for Linux. However, I am very curious about one thing. Are the changes written to the MSR registers permanently, or do they have to be set again at every reboot or cold boot? If the changes are committed and written to NVRAM--effectively replacing what is currently stored in NVRAM--then perhaps using those tools with a Linux Live USB or DVD bootable distro would get the job done for Windows users as well.

If Linux hacks (or UEFI shell hacks) can eventually lead to a fix that we can use to break, disable, circumvent or remove Secure Boot and Secure Flash and firmware signature enforcement, that would be even more awesome. Then we could flash our own unlocked BIOS like we have in the past. If we had that luxury right now we would still need Alienware to assist us with fixing the fan tables, but not having the correct default CPU power settings would be largely irrelevant.

Dell,

Any ideas on when a new bios will be released for the Alienware 18?

I understand it is the holidays, but my hopes of getting a new bios before Christmas is probably not going to happen.

I have purchased numerous laptops / desktops of Alienware and Dell, but this will be my last if Dell decides to ignore this issue.