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17" Dell XPS L702x + GTX970@4Gbps+c-mPCIe2 (PE4C 2.1) + Win7 [rossysaurus]

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Now Windows has detected m GTX970 as an NVIDIA 6800 LE and installed drivers for it but NVIDIA will not recognise it....

Another problem I have is when my laptop restarts the eGPU stops completely; no fan noise, no action, and more importantly POST or no boot, just a black screen.

Ive tried all the SW1 PERST# switches (no effect except it prevents normal startup as well)

Ive only found success with SW2 CLKRUN on #2. #1 and #3 do no boot at all.

Nothing I do will make the eGPU remain active during restart, nor reactivate during restart.

Can anyone help as to what the hell is going on and what I should do!?

P.S - hotplugging is impossible as my keyboard is holding in my mPCIe card and if I remove the keyboard my laptop will not boot.



Ahem, yeah, it works.

Specs/setup:Zotac GTX970

PE4C 2.1 (not PE4L), mPCIe into WWAN port.

Dell DA-2 220p power supply.

17" Dell XPS L702X, i7-2630QM 2.0, 6GB RAM, GT550M dGPU

Windows 7 professional


I still cannot restart my laptop, I get black screen and no post. Shutdown/startup works instead, or unplugging mPCIe before the screen goes black, selecting "setup 1.3" - "chainload startup.bat" then hotplugging during scan.

Switches were set to SW2 (CLKRUN) - 2, SW1 (PCI delay/PERST) - 1/off. PC would not boot if SW1 was in any other position, would boot if SW2 was in 3 but 2 worked better (less delay).

This took about 15 hours to get working, although 14 hours of that were failures.

This took half a bottle of scotch whisky.

Steps taken:

1. fail 400 times

2. undo all your past failures.

3. uninstall dGPU from device manager and uninstall NVIDIA graphics drivers completely, preferably by running "display driver uninstaller" in normal mode. Disable device manager auto install (open devices and printers, right click your computer icon, click device installation preferences, click NO - Never install). run "display driver uninstall" again, this time select safe mode.

4. restart or shutdown/startup if you have boot issues. Device manager should then install your dGPU as "generic VGA adapter". Shutdown again.

5. plug in mPCI card. Boot to windows.

6. windows should detect your graphics card as "generic VGA adapter". shutdown.

7. restart into Setup 1.3.

Setup 1.3 - F3 saves to chainload settings.1. Go to PCI compaction, select 32-bit 4gb limit.

2. Select "ignore dGPU"

3. run PCI compact on eGPU only.

4. Go to video adapters, disable dGPU. press F3.

5. Go to PCI settings, enable Gen2 on eGPU port. press F3

6. Go to chainload, select MBR (not MBR2, this gave me HDD not detected errors)

7. open startup settings, select fast boot.

8. Click test run, it should OK everything.

9. Go to chainload, click test run, it should take you back to the "boot windows or setup 1.3" menu. Click windows.

Windows/Driver install

1. Windows should now detect your external graphics card with no Code 12 error, though may have code 14 (needs restart).Your dGPU should not appear.

2. Install NVIDIA drivers. reboot though 1.3 chainload startup.bat. Reboot again though 1.3 chainload startup.bat.

3. System may give you error 43 (device disabled due to error report). Put the computer to sleep. unplug mPCIe card once asleep, replug, then resume from sleep. wait 2 minutes and the error should clear.

This is the stage I am at.

Unusual problems encountered:

Windows detected my GTX 970 as a 6800 LE, a standard 6800, a GeForce networking adapter, a 3d graphics adapter (apparently not the same a s VGA adapter) and refused to detect it at all. all of these were fixed by right clicking the device and selecting "update driver" - "I will pick driver" - "select driver from list" - "Generic VGA adapter. If that didnt work a reboot did.


I still cannot reboot without black screen before POST + no boot. Biggest problem. Does anyone have a solution?

Sleep sometimes is disabled which prevents sleep/resume hotplugging. it appears to be related to the state/error code shown by the graphics card though i haven't worked it out yet.

Benchmark results


When i have some more time I will update this thread with more results. the only benchmark i have run so far has been 3dmark firestrike, with a result of 7705 total, 9760 graphics, 6653 physx (CPU), combined 3328.

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Hi guys,

It seems the only reliable way for me to activate the eGPU is to sleep/hot plug/resume with SW1 and SW2 on #1. I am completely unable to use the eGPU from boot.

Im sure there is a way to set the SW1 and SW2 switches to enable use from boot to windows but I cant work it out.

I did DSDT override (huge thanks to angerthosenear for such a clear guide) which seems to have done a whole load of nothing, but at least I can discount it as a problem factor.

CLKRUN delay (SW2) seems to allow it to boot into setup 1.3 without hotplugging but not into windows (just reinstalls as generic VGA adapter). SW2 #1 prevents boot, #2 allows bot into 1.3 and onto windows but with no eGPU support, #3 does the same as #2 but slower.

Can anybody explain if PCI reset delay would be useful? So far all it seems to do is prevent the laptop booting if used without SW2 and slows down boot if used with SW2.

Also i noticed some sockets labelled J2 and J3; are these jumpers for something and if so what do they do?

I really wanted to avoid hotplugging the mPCIe card so any help with getting it to boot would be great.



EDIT: I've finally got it all working perfectly from boot with no hotplugging. YAY!!!

1. I disabled port 1 (used for eGPU) in my bios.

2. set SW1 (PCI reset delay) to position 1 (off), SW2 (CLKRUN) to position 2 (short delay).

3. I added a "port 1 hot reset" to my Setup 1.3 startup.bat

Now it boots perfectly.

I think this works because it prevents the laptop from detecting the eGPU during POST but detects it before loading windows.

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Hi guys,

Sorry for the long break in communication and updates but I work in retail and it has been manic,plus I knew I was about to install a new SSD drive with a clean install of windows so I wanted to document it from a fresh start so none of my instructions are workarounds for quirks in my install.

Parts used:


PE4C 2.1b with mPCIe adapter

Dell DA-2 220 watt power supply.

Setup 1.x from Nando4


1. Restart computer will cause a no boot. Use shutdown then start up again instead.

2. Sleep and hibernate don't work either.

3. Your shitty inbuilt keyboard will no longer fit flush. although it still works it is advised to use an external keyboard.

4. Your laptop will be less portable unless you are happy to leave the mPCIe card unscrewed.

Quirks, workarounds and optionalbits:

1. The l702x uses a dynamic max TOLUD which means it auto adjusts the size of the TOLUD to whatever is plugged into it when it starts. Now this should mean we don't need to do any DSDT override, except the laptop will not boot if it detects the eGPU -_- .

With the modified A19 bios you candisable the dynamic TOLUD and set the max TOLUD size, though it seems like that feature does not work at this time, unless I am doing something wrong.

2. My laptop has the modified A19 BIOS.This is not essential but I find that disabling my PCIe Port 1 in the BIOS (F2 at startup, advanced, southbridge config, SB PCIe config,PCIe port 1 config, disable) then re-enabling it in setup 1.x with a hot reset can make eGPU detection at startup more reliable.


This is really easy. I've listed the steps below but it can be hard to visualise.

You can follow this guys video up until the 4:25 mark.

Here is another video guide. You do not need to remove the palm rest or keyboard cables, just lift the keyboard through the gap in the palm rest.

1. Flip the laptop over, remove the RAM/HDD cover.

2. To the left of your hard drives there is a screw that holds in your DVD/Blu-ray disc drive. remove this screw, then pull the disc drive out.

3. Where the disc drive used to sit are 3 small screws in a line holding the palm rest to the chassis. Remove these three screws.

4. Flip the laptop onto it's side and push on the little button shaped piece near the screw holes. This will lift the palm rest. Shove a credit card or spudger into the gap between the chassis and the palm rest. slide the card all the way around the palm rest to pop up all the little catches until the palm rest is free.

5. VERY CAREFULLY hinge the palm rest towards your chest. All the cables (power, touch pad and quickset buttons) attach under the touchpad area. If you lift the palm rest incorrectly you could damage these cables and your computer will not turn on again!.

6. VERY CAREFULLY lift the keyboard up and through the gap where the keyboard used to sit. The keyboard cable is quite short so be careful.

7. Place the palm rest back down with the keyboard now on top of the palm rest. Click the palm rest back down. This should leave the keyboard free to be lifted so you can see and access the WWAN port.

8. Replace the 3 screws in the bottom of the palm rest, then replace the disc drive and disc drive screw.Be careful as the keyboard no longer lays flush and may damage your screen if put under too much pressure.

9. replace the RAM/HDD cover.

Installing the eGPU:

Step 1 > DSDT Override

If you follow this guide it is easy. It talks about having all the GPU active at once but I have not tested this. From what I have read splitting the PhysX across two GPU does not yield that great a performance boost.http://forum.techinferno.com/diy-e-gpu-projects/3539-guide-dsdt-override-simultaneous-igpu-dgpu-egpu.html#post49833

Step 2 > Install Setup 1.x,following the instructions sent to you by NANDO4.

Step 3 > Uninstall NVIDIA drivers,graphics card etc.

1. prevent device manager auto install:This is to stop windows from reinstalling your dGPU every time you uninstall it. Open "devices and printers", right click on your computer icon and click "device installation settings".Click "no..." and "Never..." click OK.

2. Uninstall your NVIDIA drivers through "uninstall a program...". NVIDIA install 4 pieces of software so uninstall the one the says "driver" and the others will automatically be removed.

3. Shutdown your computer

Step 4 > Attach your eGPU.

Plug your eGPU into the WWAN port under your keyboard.

Flick the SW2 Switch to position 2 on your PE4c 2.1b. This enables CLKRUN delay which allows the computer to boot without hot plugging.

Screw the mPCIe card into the WWAN port using a small screw.

Step 5 > Run Setup 1.x

1. Start the computer. at the options screen DIY eGPU Setup 1.x.

2. Select “menu based”.

3. From this point on you will need to load some instructions into the chainloader. to do this press F3.

4. Select PCI Ports > hot reset >P1 (NVIDIA) . press F3 once completed.

5. Select PCI Ports > Gen2 speeds >select Port 1 (NVIDIA), confirm retrain. press F3 once completed.

6. Select PCI compaction > Select Endpoint 4.0GB. Select ignore [dGPU]. Run PCI compaction on iGPU and eGPU. accept the red warning notice to disable dGPU once completed.

7. Select Video Cards > disable dGPU by pressing enter on dGPU. Press F3.

8. Select startup.bat, select speedup. Press F3.

9. Click “Test Run”.

10. Select Chainloader, change to MBR1. Select “test run”.

11. This will return you to the booting options menu, this time select windows 7.

Step 6 > Configure windows

1. On first boot it will detect the graphics card and install it as generic VGA adapter. Shutdown your computer (do not restart, restart will cause no boot).

2. Startup your computer, select setup1.x, then select chainload, then select windows 7. Windows will now detect your graphics card properly but will not install graphics drivers for it (because we told it not to).

3. Download the latest driver for your card from the NVIDIA site. Run the installer, selecting advanced,then tick clean install. If the installer wishes to restart, shutdown your computer before it auto restarts, then start it up again going through setup 1.x, then chainloader, then windows 7.

4. Once installed you will need to shutdown your computer, then start it up again going through setup 1.x,then chainloader, then windows 7.

Check in device manager, you should see GTX 970 listed under graphics devices with no warning symbols.Success! Press windows key + P to select "projector only"to test it is working to your external screen.

DA-2 Power limitations:

The GTX 970 is a hungry beast, and although NVIDIA listed its TDP as 150watt it actually draws over 300watt on full load. This can cause issues with the Dell DA-2 power supply.

In addition the DA-2 is not designed to deal with rapid changes in voltage requirements, which can cause power starvation to your card and BSOD.

1. NVIDIA control panel:

open the NVIDIA control panel and select "manage 3D settings.

Select "prefer high performance NVIDIA Processor”

Scroll down the list of settings until you see "Power Management Mode. Select "prefer maximum performance". This limits reduces the amount of voltage ramping and voltage changes and improves stability.

2. MSi AfterBurner:

Use this tool to limit the power requirements of the GTX 970. By default it can boost the power requirements over 150 watt and outrun the DA-2 power supply.

To the right of the power limit slider is an arrow, click this, then uncheck the "link" button.This allows temps to reach the default 79*c even when running at reduced power limits.

adjust the power limit to 80%. This will limit the constant running to 80% but still allow it to boost to 99%. 80% was found by my trial and error so YMMV.

adjust the core clock to -100 (make sure you put te minus in!) This will reduce core clocks to the reference 1077mhz. (different cards are overclocked to different limits so YMMV, adjust accordingly).

Click apply, save it to a preset. Test, then click the "apply overclock at system startup".

3. Monitoring:

I use GPU-Z to monitor what the card is doing so if I get a BSOD I can try to work out why.

Run GPU-Z, click sensors, then click"log to file" down the bottom. this will log details of the cards performance and vital signs to a text file for reference later.


Benchmark results:

Firestrike (default) @ 80% power (99% peak), -100 clock (peak 1177mhz) - 8802 Graphics http://www.3dmark.com/fs/3372912

Firestrike (default) @ 100% power (109% peak), Stock clock (Peak 1278mhz) - 9724 graphics http://www.3dmark.com/fs/3372937

Firestrike (default) @ 106% power (116% peak), +100 clock (peak 1377mhz) - 10220 Graphics http://www.3dmark.com/fs/3372960

Firestrike (default) @ 106% power (118% peak), +200 clock (peak 1478mhz) - 10625 Graphics http://www.3dmark.com/fs/3372996

This gives us about 80% PCIe efficiency at stock clocks.

This also puts my laptop 1500 points above the GTX 970m and at the same level as a GTX 980m.







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@rossysaurus , thank you for posting your experience. Would you like to post some pictures along with your guide? It helps to bring the whole guide to life.

There could be some more performance there for your GTX970.

Is it a basic 8.11" vanilla Zotac GTX970, not their higher end AMP version? If so, then if you are being TDP throttled, rather than temp throttled, you could flash it's NO LIMITS bvios from Extract and Flash GTX 970 and 980 Firmware - NOLIMITS and GameStable to get more OC performance out of it.

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Hi Nando4,

Pics added. Sorry for the mess; I've got building work going on in my house so everything is covered in dust.

I've seen this no limits BIOS before but I think the power supplied from the DA-2 is more restrictive than the BIOS limitations.

Until I have done more testing with the current bios and power requirements + DA-2 I will not be overclocking the GTX 970 for gaming. For the benchmarks above I just added a +100 clock speeds to see if it would crash, I wasnt actually trying to overclock and I have no idea as to the overclocks long term or in game stability.

Until I have identified what is causing the BSOD during Far Cry 3 at stock clocks I do not intend to overclock for gaming.

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Unusual problems encountered:

Windows detected my GTX 970 as a 6800 LE, a standard 6800, a GeForce networking adapter, a 3d graphics adapter (apparently not the same a s VGA adapter) and refused to detect it at all. all of these were fixed by right clicking the device and selecting "update driver" - "I will pick driver" - "select driver from list" - "Generic VGA adapter. If that didnt work a reboot did.

I had similar problem on L502x, and I think I found the reason:

The GTX 970 would show up with an incorrect hardware id when it is just powered up. If you power the card up, wait for at least 1 second, and reset the pcie port, you will see the hardware id change. After that it is guaranteed that you will got a 970 detected.

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