Battery Life: Better than the L501x

As mentioned earlier, Dell shipped us a 90Wh (the website states 92Wh, but our battery rates itself at 90Wh) battery for this review. However, we still have one of their 56Wh batteries from the previous XPS models available, so we tested both configurations. With the move from dual-core Arrandale to quad-core Sandy Bridge, plus a faster GT 540M GPU and HD 3000 IGP, we weren’t sure what would happen to battery life. It turns out that even sticking with the 6-cell battery, the L502x surpasses the L501x in all three of our battery life metrics. That’s good, because the large bump on the bottom of the laptop that the 9-cell upgrade brings into play is a real drawback. Here are the results.

Battery Life - Idle

Battery Life - Internet

Battery Life - H.264 Playback

Relative Battery Life

We’ve noted in the past that Sandy Bridge really improved H.264 playback power/battery requirements, and that shows up in our charts again. Compared to the L502x with a 90Wh battery, the smaller ASUS U41JF and its 83Wh battery still comes out ahead in our Idle and Internet results (though keep in mind that the U41JF has to throttle the Core i3 clocks way back to get those results). In the H.264 test, however, the 90Wh Dell comes out with more than a one-hour lead over the next closest competitor.  Even looking in Bench, the only laptops we’ve tested that offer better relative battery life for H.264 decoding use either Atom, Brazos, or CULV processors—and the dual-core SNB chip also does better than the quad-core SNB chips. Those are all far slower architectures, so the fact that SNB is even in the discussion is a feather in Intel's cap.

Battery life in general isn’t class leading for the XPS 15, but it’s good enough to satisfy most mobile users. With the standard 6-cell/56Wh battery, you can get 3.5 hours of video viewing, up to  4.5 hours of web surfing (more if you’re on simple web sites), and nearly six hours of idle battery life. Buy the larger battery and you’re looking at 8.5 hours idle, over 7 hours of Internet surfing, and nearly six hours of video playback. The relative performance of the two batteries also scales almost perfectly with cell count and capacity—the 9-cell lasts 52 to 63% longer than the 6-cell.

Rounding things out, we also tested a few other items, again with both batteries. In simulated gaming (looping 3DMark06/03), the L502x manages just 59 to 64 minutes on the 6-cell battery and 86 to 96 minutes with the 9-cell battery. Lower loads are clearly where hybrid laptops excel, so the combination of an active GPU and quad-core SNB is the exact opposite of a low load. Note also that unlike the GTX 460M, the GT 540M can run at full speed even on battery power (hence the low battery life). Setting the LCD to 100% brightness (instead of 40%, which corresponds with 100nits), idle battery life drops a rather large 27%, or in other words the LCD uses an extra ~3.9W for a 150nit increase in backlight intensity. That’s a lot more than we’ve seen with other laptop LCDs, but the 1080p panel is higher quality and gets brighter than much of the competition so we’re willing to cut it some slack.

Better Midrange Graphics, But Still Midrange A Good LCD; Okay Temperatures and Noise Levels


View All Comments

  • softdrinkviking - Wednesday, April 20, 2011 - link

    seem to accentuate any flaws or slight color vairiances to me.

    i definately prefer matte so that i don't have to deal with the glare, but i noticed that anti-glare fliters, or matte finishes tend to exaserbate light bleeding in spots and so on.

    i noticed this most on TN screens that have been used for a couple of years and are starting to get a little worn out; the glossy finish seems to hide the deterioration to me.

    has anyone else noticed this, or do i have a unique situation/i am going crazy?
  • JarredWalton - Wednesday, April 20, 2011 - link

    The one issue I have with matte is that if you happen to brush against it with an object you can leave a "scar" -- not a scratch, but just a mark in the matte finish. If you have a poorly built laptop where the keyboard or palm rest happens to press against the LCD, that can also cause marking -- on glossy as well, but it's more noticeable on matte. Heck, I have a "scar" on my 30" 3007WFP that happened when I was packing for a move. Yeah, ouch! The old Dell Studio XPS 16 had the other issue, with keyboard marks showing up on the edge-to-edge display cover.

    Anyway, having seen both the Clevo P150HM/151HM and the XPS 15 panels side by side, I'd definitely take the matte and run that risk.
  • JNo - Friday, April 29, 2011 - link


    I have a Dell 2405 FPW with matte finish. Spent around £800 on it back in the day but don't regret it a bit as it's still a contender - rare even now to find 24" with matte IPS that can go portrait and has a USB hub and card readers built in. Anyhoo, I digress... I also got scars on it once or twice and I couldn't for the life of me 'wipe' them away but if you google around you can find solutions...

    Amazingly, I found using a clean (try new) white or colourless rubber on the screen and rubbing gently in the direction of the scar worked. Wipe before and after with a lint free micro-fibre cloth and just a teensy bit of water. It literally made the scar disappear and the monitor looks as new again. I sh1t you not - worth a try.
  • vol7ron - Wednesday, April 20, 2011 - link

    posts like this too. Reply
  • Flunk - Sunday, April 24, 2011 - link

    I've found quite the opposite. My matte displays seem to hold up much better than the glossy. The glossy ones seem to pick up scratches, marks and smudges very easily and they show horribly. The matte finish tends to disguise the little things. Reply
  • AmdInside - Wednesday, April 20, 2011 - link

    I bought the L502x and love it. One great thing about Optimus is that since the Intel graphics is still used for 2D, Intel Quick Sync is possible with this laptop. It is amazing how fast it can convert video for a laptop.

    I guess my main complaint is that I preferred the previous generation keys better over the newer smaller softer keys. Dell has regular sales on XPS laptops which really brings down the cost of this laptop. I got a fully loaded Dell XPS 15 L502x for around $1300 after taxes. Just love love love the 1080p screen.

    Oh, and I personally am not a big fan of super thin laptops. They just don't feel right when they are on my lap. I like my keyboard to be raised a little so the thicker body of the l502x suits me just fine. I wish Dell hadn't dropped the 14" model as I would have bought that if it was still available with Sandy Bridge for portability but the 15" is fine.
  • therealnickdanger - Wednesday, April 20, 2011 - link

    I had a 17" Dell years ago with a 1080p screen and a 7900GT Go. It did OK, but ultimately, I don't think I would ever buy another 1080p laptop without a high end GPU. If the L502X had a higher GPU option, it would be perfect! I would probably order this laptop with the 768p screen and upgrade to the 540 and play games with max settings at native resolution. Reply
  • aneuwahl - Wednesday, April 20, 2011 - link

    there is a puzzling thread on Dell's support forum here
    about an unsolved problem regarding the USB3.0 ports. They seem to fail randomly becoming completely inactive till next reboot.

    I'm curious if during the test anything like that was noticed.
    I've just bought a L702x and I have the same problem. Dell replaced my motherboard (not the USB3.0 daughterboard), but the issue - with reduced occurency - is still there.
  • JarredWalton - Wednesday, April 20, 2011 - link

    Is it possible they're going into a power saving state and not coming out of it? I actually don't have any USB3 devices on hand, so I didn't encounter this, but I should be getting something soon. Let me get back to you.... Reply
  • jcannon1018 - Wednesday, April 20, 2011 - link

    Supposedly, under all programs there is a folder for the usb 3.0 controller and clicking on it will bring up a settings panel for the controller. On that panel there is a disable power management function, checking apparently resolves the issue of the ports becoming unresponsive. I thought that sandy bridge had native support though? Reply

Log in

Don't have an account? Sign up now