E6540 Owners Thread

Hey guys
Really hoping someone who used to frequent here may be able to help. I've just picked one of these units up at a great price 'fully working', with the intent it'd be my father in laws new main machine. It comes with a Dell 130W charger, and original battery (which is ~75% worn and recommends a new one both in Dell Command Power and BIOS/Testing due to wear level and is 'reaching the end of its usable life'. It's the 4810MQ/8790M variant.

The machine would be absolutely perfect for the father-in-law, however the machine has a few major quirks which are leaning me towards returning if I can't resolve:

1) The machine was hard freezing with newer AMD drivers, I THINK I have resolved this by leaving Windows 10 as a a fresh install with all the Dell Command Update drivers, and updating to the latest BIOS (A27 in the UK). <Solved?>

2) When I first boot the machine, the machine will REFUSE to use Turbo on the i7, it'll sit between 2200-2700MHz, and if I apply a stress test, it'll drop the core speed right down in short order. I discovered that sleeping the machine seems to restore working Turbo boost (yay) and it'll mostly play nice at higher clocks, but extended CPU stress tests will sometimes drop it back down to 800-2000MHz, and if that happens, performance doesn't restore back to the full fat experience. Sometimes however it'll run absolutely fine and the CPU will play nice at this point.

3. If I run a GPU stress test, ie Heaven on low for a couple of hours, it'll initially appear fine but after a while ie couple of hours, the CPU will usually drop again to that 800MHz 'life saver mode' and refuse to come back up to full performance or even normal 2.7GHz until I shut the machine down and start her up again (and then do the whole sleep cycle etc again to get Turbo working). This is even if the GPU maxed at around 80 degrees and the CPU didn't hit the thermal protection point, so no thermal reason for this to happen (and nor does it resolve once the CPU/GPU cool).


I've tried running the BIOS Diagnostics and aside that battery, they basically advise all ok.

Has anyone seen this before and solved it?

I've seen enough to see that this seems to be power related in some way, rather than heat, and I did read a few things which suggest some Dells have been known to throttle the CPU if that battery is dying or the power supply is non genuine; however in this case I have another (almost new) genuine Dell PSU here from another much newer machine (also 130W) and it still does the weird booting without turbo so I don't think the problem is the PSU at least, or I'd not expect to see the same issue with both.

I could try replacing the battery, however I am loathe to throw money at an old machine that is already not working right out the gate incase it's the motherboard when I can return and let the seller resolve, BUT it seems like a decent machine, and I did get the machine for a good price that makes me want to ask first because if this can be resolved it'd be perfect, and it's so close!

 

Hi @Alexrose1uk,

I believe what's happing is that you don't have the correct power supply for your CPU. You need a 240w, (Dell PA-9E), for your system. This should reslove your throttling problems.

https://www.ebay.com/sch/i.html?_nkw=dell+240w+adapter&_sop=15&rt=nc&LH_BIN=1

 

I did consider this, but upon doing some research, it seems the 130W is what this model shipped with, so should be enough
https://www.notebookcheck.net/Review-Dell-Latitude-E6540-i7-4800MQ-HD-8790M-Notebook.97595.0.html
https://www.dell.com/community/Latitude/best-charger-for-Latitude-E6540/td-p/5848116

It also doesn't explain why the turbo boost kicks in after sleep mode, but CPU is 'capped' and throttled (especially under full load) before that. BIOS recognises the 130W and gives no warnings.

The machine also behaves the same with or without the battery installed. I did try removing the battery incase that did something, but beyond discovering the BIOS battery needs replaced (haha) it didn't help.

 

I purchased my M4800 used and it also came with a 130w PSU. I was also having throttling issues that went away with the larger PSU. If you go to dell.com, click on "Support" and enter your service tag number, you will get the page that shows the original configuration for you laptop, including the PSU that was originally shipped with the unit.

Although it is possible that the previous owner upgraded an i5 CPU that has lower power requirements than the i7-4810MQ that you now have.

 

As above even the 4800mq models came with a 130w.
I've just checked the laptop and the back sticker advises 19.5v/6.7A (130W). I also rechecked the service tag and that also states 4800MQ and 130W under system config.

I'm loath to throw £50 ($70) at a higher wattage PSU, when that's not what this even came with as stock. Appreciate the thought though, I did wonder about the PSU, hence trying out the other 130W I knew was much newer and genuine, but no dice.

This does seem to be power related but I'm erring more towards battery/motherboard I also believe the machine is meant to flash a message at you on boot if the PSU detected is OEM/not powerful enough and no warnings given, in fact all diags on the power supply show fine.

 

Ok well I took the time to read the entire thread last night and seems like I wasn't the only one to encounter the 800mhz'ing issue but with no solid resolutions. The turbo quirk however does appear to be more unique.

I think I will return this unit and try and find something less quirky and without issues!

If it just got hot and throttled, I could have dealt with that, but the wierd quirks and getting 'stuck' at lower clock speeds etc, plus the potential of those random hard locks to return? Nothing I've done has got the machine to play normally so I just don't want to take that risk.

 

I definitely would not recommend this laptop. The throttling issue may be corrected by using Throttlestop. But sometimes the Dell has mind of its own and ignores your configurations and then you have to put the device to sleep and wake it up before accepting Throttlestops inputs. Very tinker intensive to put it lightly, and not to mention you have to use older AMD drivers as well, since you've encountered similar issues with the latest drivers as I did few months ago.

 

Yeah on reading through I began to realise this is not a good 'just work' machine, and the turbo not working quirk makes me thing that machine is just not right. I'll be going for something else. as I need something that won't drive the father-in-law mad. He's retired, he just wants the thing to work.

 

Personally, I have had better (read reliable) experience with something in the likes of Elitebook 8770W and Precision M6700 notebooks, but finding one in a respectable condition is rare these days and if find one often those online sellers ask pretty penny for them. About the E6540, have you returned it yet?

 

The E6540 is boxed up ready to go, waiting for their courier to come grab it
I've managed to nab a M4800 instead for a reasonable cost, which seems substantially better built at the very least!