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E6520 Owner's Thread

Discussion in 'Dell Latitude, Vostro, and Precision' started by pbdavey, Mar 29, 2011.

  1. Khenglish

    Khenglish Notebook Evangelist

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    Hmm 2133 sounds too high for the low voltage laptop memory runs at. I think I'll just go for 1866.
     
  2. futchi

    futchi Notebook Enthusiast

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    I tried to flash 1 stick to 2133MHz cl=12, and bios shows the memory really running at 2133MHz. But it's very unstable, bsod happened when windows boot.

    Then I plugged in the other stick and flash back to 1866MHz.

    The conclusion is E6520 can support both ddr3-1866 and ddr3-2133, but my samsung stick cannot run at 2133MHz.
     
  3. Scott_RC-TEK

    Scott_RC-TEK Notebook Deity

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    Guys, why in the world would you try to overclock memory with a higher CAS? Are you just interested in seeing the highest number? In reality, these mobile processors being discussed will not go above 1600MHz no matter what the utilities are telling you about the memory. All you are doing is stressing the components and making the latency higher, which is counter productive.

    Many people do not realize the CAS being lower is more improtant than the bus speed. 1333MHz CL6 or CL7 memory will always beat out the 1600 or 1866MHz CL11 or CL12 since the lower CAS in this example can handle almost twice as much data in the same amount of clock cycles. So in the end, you may have what appears to be faster memory with the higher bus speed (thanks to good marketing by the memory companies), but the processor will not handle it any faster and the -5% to +3% difference in data transfer does not justify the risk to the hardware and voiding the warranty.

    This is just my opinion.

    Scott-
     
  4. Khenglish

    Khenglish Notebook Evangelist

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    The higher the memory frequency, the higher the bandwidth. 800mhz CAS 5 will have the same latency as 1600mhz CAS 10, but the 1600mhz ram will have 2x the bandwidth and provide significantly better overall performance. There is no false marketing, just that some applications may have low bandwidth requirements, making latency the only real factor in performance.

    I plan on using the eGPU at home, but when I use the laptop somewhere else I'm going to have to depend on the HD 3000, which uses the system memory. All video cards care about is bandwidth, not latency. Look up graphics card memory latencies, they are ridiculously high (CAS 20+) to get as much bandwidth as possible. Outside the HD3000 performance though, benchmarks have shown that higher performance memory doesn't do a whole lot for system performance.

    Thanks futchi for risking your memory to learn what the e6520 can handle. It was interesting for sure.
     
  5. Scott_RC-TEK

    Scott_RC-TEK Notebook Deity

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    Video, especially 3D, relies on speed, not so much bandwidth after a cerain point.

    Yes, the latency in time is the CAS latency divided by the clock frequency. Therefore, the following are the important numbers to consider regardless of bandwidth since you're limited to the bandwidth of the processor, not the memory:

    CL7 cycles @ 1066MHz/sec = .0066 x 10 = 6.60 nanoseconds

    CL7 cycles @ 1333MHz/sec = .0053 x 10 = 5.30 nanoseconds

    CL9 cycles @ 1333MHz/sec = .00675 x 10 = 6.75 nanoseconds

    CL9 cycles @ 1600MHz/sec = .0056 x 10 = 5.60 nanoseconds

    CL11 cycles @ 1600MHz/sec = .0069 x 10 = 6.90 nanoseconds

    CL11 cycles @ 1866MHz/sec = .0059 x 10 = 5.90 nanoseconds

    CL12 cycles @ 1866MHz/sec = .0064 x 10 = 6.40 nanoseconds

    CL12 cycles @ 2133MHz/sec = .0056 x 10 = 5.60 nanoseconds

    Can you see the pattern here? This is what I mean in regards to marketing. Regardless of CAS and bandwidth, all these sticks are pretty level across the board when it comes to real world throughput. In regards to the i7 2720QM, I would much rather run CL7 1333MHz than CL11 1600MHz for the obvious reasons above since the latency speed bump would outweigh the small bandwidth improvement on the higher freq. memory. To see a small but noticeable difference while peaking the i7 2720QM 1600MHz FSB, one would need to find some CL8 1600MHz (5.0ns) memory, but the cost would not be cheap. In the end, we are still talking about 3~5% performance differences so it means nothing at this stage unless you simply want to show your friends some high clock numbers.

    Scott
     
  6. futchi

    futchi Notebook Enthusiast

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    The specifications in intel website show 2720qm only supports 1600MHz or lower, and i7-2620m and i7-2600 support 1333MHz or lower.

    But in desktop p67 platform, one can use memory higher than specification by changing memory ratios. Now we find that qm67 (hm67 also reported) platform can also use memory higher than specifications, and the bios of E6520 will automatically change the memory ratios to support 1866 and 2133 memory.
     
  7. SwagNet

    SwagNet Notebook Enthusiast

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    Is the Kingston HyperX RAM 1866 compatible with the e6520?
     
  8. Moodib

    Moodib Newbie

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    Okay, so I'm a retard and can't figure out how to disable the onboard graphics and have the NVS4200 on instead. Any help? :confused:
     
  9. futchi

    futchi Notebook Enthusiast

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    Yes, one of the comments of hyperx 1866 in newegg mentioned it is OK for e6520.
     
  10. Dreamliner330

    Dreamliner330 Notebook Evangelist

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    Go into the BIOS and disable OPTIMUS from the VIDEO screen.
     
  11. Moodib

    Moodib Newbie

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    My one question is then, if Optimus is on, does the Nvidia kick in for business applications and games or is it always the intel graphics?
     
  12. Dreamliner330

    Dreamliner330 Notebook Evangelist

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    ^From my understanding...if the information being requested from the video controller is more than the Intel card can handle...it will kick over to nvidia.
     
  13. DJWoX

    DJWoX Notebook Enthusiast

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    Hi whaere i can get 2 HDD bay but not paying 50USD but with thet plastic
    than it doesnt look like this
    [​IMG]
    ebay ? i find only 3 versions and it all loks same :(
     
  14. Dreamliner330

    Dreamliner330 Notebook Evangelist

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    ^You cant. There is a reason the ones from newmodus cost $50. They are designed to be as close as possible to Dell. You should be thankful you can get it for only $50. Dell wants over $100.

    Quit being cheap, buy the one from newmodus. Quality matters, you get what you pay for.
     
  15. jcthorne

    jcthorne Notebook Geek

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    I will say that the one from newmodeus is very high quality and includes a blue HD activity led as well as fits the Dell 62xx series perfectly. Looks OEM.

    They also have a very nice cable for connecting your ODD on the rare occaision you need it.
     
  16. liamfr

    liamfr Notebook Enthusiast

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    Bit of a breakthrough on the BSOD front when docked. This appears to be fixed now.

    This was a persistent issue on the 6520. Updating BIOS and drivers etc to latest everything reduced but did not eliminate the issue and it was still happening once or twice per day.

    Finally it would appear we have the solution.

    It turns out that there are different Dell part numbers for the port extenders with model number PR02X: and although the appear externally physically identical they are *NOT* interchangeable.

    Dell P/N F310C A03 is *NOT* on the compatibility list for 6520s
    Dell P/N 4RTRN A00 is the officially compatible one

    We were shipped the F310C ones which, it would appear, are the root cause of the BSOD issue on 6520s and also quite probably on 6420s - we've started to get reports from 6420 users of occasional BSOD too.

    I swapped the PR20X for one with Dell P/N 4RTRN A00 and hey presto, no BSOD in over a week, using 2xDell DVI monitors and 1xSony VGA monitor when docked.

    Why they didn't change the model number to make this more obvious is beyond me because the two port replicators appear absolutely identical (apart from the Dell P/N number on the label on the base)

    HTH

    Liam
     
  17. jcthorne

    jcthorne Notebook Geek

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    PRO2X is the E-Port Plus dock. Any idea if a similar compatibility issue exists for the E-Port PR03X?

    The dell web site shows no sub models within each of these and says both are compatible with all E series Latitudes. This is the first time I have heard of any E series not being compatible with all E series docs.
     
  18. liamfr

    liamfr Notebook Enthusiast

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    That was news to us too (and to most of Dell support. It took them quite a while, several weeks in fact of trying everything else including changing motherboards etc, before they came up with that).

    I'm afraid we don't have any PR03X so I don't know about those.
     
  19. Rykoshet

    Rykoshet Notebook Deity

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    take the cover off your DVD RW and put it on your HDD caddy.
     
  20. AngryXPS

    AngryXPS Newbie

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    Anyone successfully found a part number and price for the backlit keyboard for these systems? Mine came from the outlet, and I made the mistake of assuming they were all backlit since none of the 200+ systems in the Outlet had that on them as an option.

    TIA for any help!
     

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