XPS 15 (Haswell) Owner's Lounge

Discussion in 'Dell XPS and Studio XPS' started by mark_pozzi, Oct 23, 2013.

  1. mastabog

    mastabog Notebook Enthusiast

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    I think you misread my post. I didn't say the battery is 51 Whr, but computed an equivalent capacity assuming a 10W higher consumption on the M3800. In other words, making consumptions equal, then the equivalent battery would have 10 Whr less, in order to make the results directly comparable.

    A few specs I've seen (e.g. here or here or here or here) show the 750M at 33W. The K1100M is listed at 45W. Same GK107 core on both, but the Geforce has some units disabled (double-precision computations are crippled on the Geforce by a factor of about 1/8).

    Can you point to the specs showing 50W for the 750M?

    Regarding WiFi, the person who reviewed the XPS is not the same as the one who reviewed the M3800.

    In theory the dGPU should not kick in during desktop, but Windows 7 and 8 use GPU processing in the Desktop Window Manager. During normal desktop browsing I'm seeing the GPU being used; actually, it's enough to just drag and move a window around to cause GPU usage. But you're probably right, that WLAN test only emulates browsing.

    However, there were reports in the past where some Nvidia drivers caused Optimus not to work properly and to keep the dGPU powered on at all times, with a lower clock. I wonder if that happened during the M3800 review. I can't otherwise explain such a big power draw difference.

    Anyone with a clue regarding this difference? The HDD is far from accounting for it (it's roughly 2.3W).
     
  2. nikbert

    nikbert Notebook Enthusiast

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    I have 16gb ram - do i still need to keep the paging file? I dont yet do any video editing or similar, and no gaming either.
    If yes (and since I've disabled the intel rapid start), can/should I convert the rapid start partition into a drive that can hold the paging file?

    PS: intel rapid start was having issues with laptop sleep - probably due to ram size > rapid start partition size.

    TIA!
     
  3. JPBJ

    JPBJ Notebook Geek

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  4. [-Mac-]

    [-Mac-] Notebook Deity

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    Even one link that you have supplied says 50W for GT750m:
    GeForce GT 750M vs 730M
    In this link 33W is TDP for GT730m while GT750m has a TDP of 50W

    Instead the link to Futuremark community is for different version of GT750m, because 2600points on 3Dmark11 is significantly lower than 3000points that GT750m of XPS15 can do.
    NVIDIA GeForce GT 750M Review - Performance

    here other link that confirms 50W for GT750m
    NVIDIA GeForce GT 750M | techPowerUp GPU Database
    NVIDIA Quadro K1100M | techPowerUp GPU Database

    Moreover, the difference between K1100m and GT750m are optimized drivers, a specialized BIOS and dedicated CAD support, also we know that they are the same chip and if you have some notion of microelectronic you would know that power consumption is directly correlated to frequency (clock) and GT750m has a clock much higher than K1100m, we are talking about more than 30%, so it's pretty normal that GT750m has a TDP higher than K1100m.
     
  5. [-Mac-]

    [-Mac-] Notebook Deity

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    Today Notebookcheck has published review of Presion M3800 (twin of XPS15) so I repost my consideration:

    Review Dell Precision M3800 Workstation - NotebookCheck.net Reviews

    It's very helpful to understand the difference between batteries 61WHr and 91WHr.
    It seems confirmed the short battery life of 61WHz it's just 3h 29min while surfing via WLAN, the XPS15 in the same situation can do 8h 50min, most likely the guilty is HDD (just a my speculation).

    The other point where I see a big difference is in the generated external heat, on the point where there is max temp on chassis XPS15 has a 27.5°C more than M3800, that's almost unbelievable.
    I was thinking a some kind of mistake, but I have seen data about power consumption, M3800 has a max power consumption of 87.6Watt while XPS15 has a max power consumption of 115.2Watt, so we are speaking of 27.6Watt more than M3800! This big increase in power consumption can justify the big difference in generated heat.
    Obviously there is a big difference on GPU performance:
    XPS15 9530 can do 3000 points on 3Dmark11.
    M3800 can do 2000 points on 3Dmark11.

    Here the link for XPS15 9530 review by Notebookcheck:
    Review Dell XPS 15 (9530, Late 2013) Notebook - NotebookCheck.net Reviews
     
  6. trofi

    trofi Notebook Consultant

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    Of course there is going to be difference. Don't forget people thta apart from hardware is the tuning of it in each laptop that also makes a great difference. Two models could have exactly the same hardware vut different benchmark results due to each company tuning clock speeds etc differently.

    I assume Dell though that people with XPS15 would refer full power to harness its power for a few tasks like casual gaming and they would use it on a table etc. But the M3800 being a workstation is a different story, it is more important for it to be more stable than getting some extra power and people that would use it as a workstation would like to move around ALOT which is actually the point of a THIN elegant workstation.

    If you want something faster albeit less mobile you get a normal workstation but if you want something elegant that it is powerful enough to run everything a professional would need and move around easily from a presentation room to the other you get M3800. Also professionals tend to work on lap or on weird surfaces so less heat generation is important.
     
  7. [-Mac-]

    [-Mac-] Notebook Deity

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    According to NotebookCheck review it seems that display supplier are 2, LG and Sharp:
    In its review the M3800 uses a display made by LG that has a less contrast than Sharp model, but it's a IPS display.
    So Owner it's better to check which display you have on your XPS15.

    My XPS has the Sharp model (it's a XPS top tier model): Hardware ID is SHP13F8.

    The LG model seems to have Hardware ID: LQ156Z1

    This explains the big difference in brightness between EU model and US model in reviews by Notebookcheck, because EU model in review uses a Sharp display while US model in review has a LG display.
    So it seems the LG has more brightness but less contrast.

    This monitor difference could explain even the difference in power consumption, because LG display is not a IGZO.
    Could be interesting to know if there is a correlation between IGZO display and 91WHr battery.
     
  8. jphughan

    jphughan Notebook Deity

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    Looks like you're dropping off the [ / QUOTE ] tag (which I entered with spaces in order to avoid that code being interpreted).

    I would honestly set Windows to automatically manage the paging file. Virtually everything I've read has indicated that Windows almost always does a better job of managing memory and the page file than humans, so leave it to its own devices. If you're running on an SSD, there's no point parking it on its own partition since it will be on the same device anyway. If you've got the hybrid drive + cache setup, I don't think there's a way to force the page file onto the SSD while your SATA operation is in Smart Response mode. If you switched to AHCI to expose the cache as an independent unit, you could do that, but making that change might require you to reinstall your OS -- and you'd lose the ability to use Smart Response. I would instead recommend killing the Rapid Start partition and then going into the Rapid Storage application to allocate the newly freed up cache space to Smart Response, which should add a bit more performance.
     
  9. seancho

    seancho Notebook Guru

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    I wasn't aware that LG was producing IGZO display panels, yet. They could be wrong about it being an LG. The biggest difference between the displays in the XPS 15 and M3800 reviews is color accuracy. They measured the XPS 15 display delta-e at 5 (claiming that it was 'trounced' by the rMBP) but the M3800 display comes in at at 1.2. The 2nd number is close to what I get on my XPS, and what Bokeh got on his M3800. NotebookCheck hasn't given any solid evidence that there are multiple suppliers of this QHD+ panel. I bet it's the same panel, and they are just getting some sample variation plus testing error.

    Does anyone NOT have the SHP13F8 panel in their XPS15/M3800?
     
  10. jphughan

    jphughan Notebook Deity

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    Nobody is claiming that the LG display is IGZO; [-Mac-] indicated it was IPS.

    I think the Delta-E difference is due to the fact that they didn't disable splendid mode, honestly. It comes enabled out of the box and the control to disable it is not in an intuitive location, so I doubt the reviewers knew about it -- which is unfortunate, because that and the likelihood that they also had adaptive brightness still enabled led them to post mediocre impressions of what is truly an astounding panel when those features are turned off. Also, a few people with professional calibrators here have gotten results on their XPS panels that match the M3800 review, but only AFTER disabling splendid mode, before which they got results that more closely resembled that XPS 15 review.
     
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