Latitude 7450 Owners' Thread

Hi guys. Have you tried 4k@60hz output on 4k tv?
My battery has 17% wear after less than 3 month, last for less than 3 hours with about 50% screen brightness. Is that normal.

 

Don't think so. My battery has 5% wear over 2+ months and lasts for about 6-7 hours. I use 'Mainly on AC' profile in Dell Command/ Power Manager and I don't rely on the battery very often.

Well, I installed Battery Bar and it extimates usage time ~4.5 hrs.

Had a very strange glitch today - suddenly display started flashing black and froze up after maybe ten seconds. I closed the lid and then opened it, which, surprisingly, un-froze it. What might be the cause? That looked serious.

 

Try a set of headphones to rule out issues with either the speakers or the cables connecting the speakers. When I had sound issues (similar to yours) they were likely driver related because these noises were both through speakers and headphones.

 

That seems like the simpliest test, but somehow I didn't think of that. Thanks.

The glitch with explorer sound I mentioned disappeared in headphones and I didn't hear any crackling yet.

 

I had around 8% wear when new, but it has not increased (but the battery doesn't get much use at the moment). Probably the best action is to run down the battery completely and then recharge it. Do this by using the computer on battery until it is low and then going into the BIOS setup until the computer switches off, then immediately recharge to full. That will enable the chip in the battery to redo the calibration. Windows doesn't fully drain the battery before automatically hibernating and sometimes this results in the battery chip's idea of empty can drift away from the true empty.

Actual run time on battery depends on the usage pattern of which display brightness is only one factor. I use BatteryInfoView to let me check the drain rate. 7W is a reasonable target under light usage but if you are only getting 3 hours then something is probably keeping the CPU reasonably busy. If you have a web browser open then see the effect of closing it. I use Firefox with AdBlock Plus and FlashBlock plus a custom hosts file to keep down the amount of unwanted web browser activity.

Edit: Also check if the CPU is running at full speed on battery. If it is then changing the maximum CPU state on battery in the Power options will disable Turbo Boost, which will save some power.

I would roll back to the previous graphics driver. Device Manager should offer that option.

John

 

Well, this is fun because with this driver I don't get 'resize-windows-on-wake' issue I mentioned earlier, but get this instead (probably).
This concludes that not only drivers picked for you by the manufacturer, but even the latest drivers (which everybody usually recommends to install/update to) could break something. Another examples are audio driver which is probably causing the crackling sounds and Nvidia soft which suddenly lost the ability to 'optimize' games and started dropping error instead as I installed the newest version. Guess I'm just having an unlucky week or something.

 

The most recent Dell drivers should be OK. They tend to be a month or two behind, possibly due to testing for possible problems.

John

 

Just wondering if the screen glitch mentioned earlier was a freeze on black screen where you close the lid, reopen and then it goes back to normal. I had this happening to me where after "waking up" the screen would be black, the keyboard would lite up, there would be disk activity but the screen would be black. Going into "power options"; "choose what power button do", "change settings that are currently unavailable", and uncheck "turn on fast startup" fixed the issue for me.

 

Sorry for the late reply, no, that freeze was when I was surfng the internet with 4-5 tabs opened. At first I noticed how the cursor was misbehaving, it looked like a very low framerate, then screen turned black with the lights blinking. Then I closed and opened the lid and suddenly it became normal.

Btw latest update fixed the Nvidia software. Also, I've now got a lot of crackling sounds out of speakers. Tried to roll back the drivers and install the latest ones from the realtek site, but that didn't fix the issue: it crackles on startup, when I turn on some music / etc. I don't notice this much in my headphones (they aren't high quality), but this looks like drivers AND dynamics are both causing this. Will buy new headphones and re-check this.

Also, I confirm that turning off c-states increases power consumption. After installing Battery Bar I can see how much battery discharge rate is, and when notebook use isn't used very intensively, on average it's higher than with c-states.

 

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