Spanky's Place :: Simple fix for Slow running M6400 Precision Workstation

Category Technical

My primary machine I use for development is a Dell Precision M6400 Workstation, with a QX9300 Quad Core processor, 8Gig of RAM, dual 7200 RPM HDDs, and a 1920 x 1200 RGB LED display. This setup allows me to run multiple VMs within which I have setup various Domino Server and Notes Designer client environments. Doing things this way allows me to have "clean" setups for different projects -I can change from Notes Client 7 LotusScript development to banging out some Java in the latest Eclipse Designer Beta and go back to a knock out some @Formula in R5 (for old customers who refuse to migrate) with nothing more than a mouse click alt-Tab combination. This machine is an absolute monster. All this power does come with a thorn -my battery life is a joke. 45 - 55 minutes max is all I get out of a (high end 9 cell) battery. This machine is a power vampire.

It also tends to run a bit warm. However lately it has began to run excessively hot, so I called Dell and they sent out a technician yesterday to replace the main system board, processor, both side boards, heat sinks, and cooling fan. I brought the laptop upstairs for him to work on (I don't like letting strangers into my office), and provided him with a portable Dell 90 watt power supply to use. After swapping out the hardware, he did a quick "does a browser work" test and called it good. I noted that my VMs wouldn't start up, but figured (correctly) that the problem was due to needing to flash the BIOS & change some settings.

Image	Expected Value	Reported Core 1	Reported Core 2	Reported Core 3	Reported Core 4
Speed	2.53 GHz	1.23 GHz	1.23 GHz	1.23 GHz	1.23 GHz
System Bus	1066 MHz	824 MHz	824 MHz	824 MHz	824 MHz

After he left, I noticed that my Windows Experience Index needed to be updated, so I ran that. Much to my horror my processor & memory indices were now showing 4.1 (previously 7.2) out of 7.9. I downloaded and installed the Intel® Processor Identification Utility. Running the utility revealed that my bad-boy QX9300 2.53 GHz Quad Core, 1066MHz FSB, 12 MB L2 Cache processor was running at 1.23 GHz. This didn't really concern me that much, as the processor is designed to automatically adjust it's speed based on workload. What really concerned me was the fact that my bus speed was 824MHz, just under 80% of what it was supposed to be. The FSB speed also effects memory access, which means that my entire system was now pig-slow compared to what it was supposed to be.

You could say I was a bit put out, but that would be a bit of an understatement. I was significantly more than that. I was livid. I knew it was too late to call Dell back (24x7 support is only true for "consumer level" issues -this was way beyond that). The support group I needed to speak with wouldn't be back in until 8AM EDT. So I shut the laptop down and carried it back downstairs to my office where I hooked it back into my "normal" work environment (external keyboard, mouse & speakers, 210 watt power supply, additional HD monitor, etc).

At precisely 8:01am this morning I called Dell support. While wading through the myriad of automated phone questions (Turing Test: machines don't loose their temper and scream at automated systems) I decided to run the test again so I would have the numbers in front of me when a human finally came on the line.

Image	Expected Value	Reported Core 1	Reported Core 2	Reported Core 3	Reported Core 4
Speed	2.53 GHz	2.51 GHz	2.51 GHz	2.51 GHz	2.51 GHz
System Bus	1066 MHz	1065 MHz	1065 MHz	1065 MHz	1065 MHz

To my absolute amazement, my machine was now running the way it should be. 2.51Ghz per core, with a 1065MHz FSB speed. Now this was much more like what it should be. I hung up the phone before I embarrassed myself, and began noodling this conundrum. What had changed between last night's frozen molasses and this morning's greased lightning? I hadn't installed or updated anything, no additional software was running, all VMs were shut down. I thought perhaps the network cable (vs. last evening's wireless) and tested that, but nothing. Quite the puzzler.

Eventually I figured out what you've already guessed (assuming you've paid attention to the clues I've given).

Bingo. The power supply. Whenever I use the smaller portable Dell power supply I get a warning on boot up telling me that I really should be using the higher end supply. I've always figured this simply meant my battery wouldn't charge at a normal rate (and it doesn't). I should have paid perhaps a bit more attention to the actual wording of the message (emphasis added):

WARNING: A 90W AC power adapter has been detected, which is less than the recommended 150W AC adapter originally shipped.

This will increase the time to charge the battery.
The system will adjust the performance to match the power available.

Please connect a Dell 150W AC adapter or greater for best sysem performance.

Image	Expected Value	Reported Core 1	Reported Core 2	Reported Core 3	Reported Core 4
Speed	2.53 GHz	1.59 GHz	1.59 GHz	1.59 GHz	1.59 GHz
System Bus	1066 MHz	1063 MHz	1063 MHz	1063 MHz	1063 MHz

I disconnected the power supply and ran the test again on battery only. Results were not nearly as good as on the high output power supply; but significantly better than when on the low-output power supply.

Several important lessons were learned here.

Lesson 1 - Be patient and don't get angry when something unexpected happens. I managed to work myself up into a pretty serious tizzie (stomping about, cursing & frothing at the mouth) last night because I was convinced that Dell sent me a lower end board than I had originally. This was neither healthy or helpful in solving the problem.
Lesson 2 - Pay attention to warning messages. I'm sure I'm not the only one guilty of arrogantly dismissing warning messages / dialogs because we "already know" what is going on.
Lesson 3 - Use good testing tools, and test under multiple conditions. Using the Intel utility allowed me to quickly prove (once I realized this was a PEBCAK situation) my theory as to the cause of the problem.
Lesson 4 - Travel with the "brick". When I travel I usally carry the light 90 watt Dell power supply in my bag. Not any more. From now on I'll take the big heavy 210 watt power supply with me. Performance, especially at a client's site, is critically important; and worth the trade-off in weight.

If you are running a high-end, multi-core processor in your laptop and not getting the performance you expect, you might want to start by checking your power supply.

-Devin