Problems with PCI express slots in a Dell Optiplex 7070

PCIe gen 3 backward compatibility is an industry standard which should not depend  on specific motherboard model.  That being said if your specific gen 2 card is not functioning normally in gen 3 slot, test the card in an old desktop pc that has gen 2 slot to verify it works normally first.  For example optiplex 7010 has Q77 chipset which has PCIe gen 2 slot.

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@amattag wrote:

Dell Optiplex 7070 MT in order to work with a framegrabber from Active Silicon:

https://www.activesilicon.com/products/firebird-coaxpress-frame-grabber-dual-cxp-6/

1. This framegrabber needs a PCIe 2.0 x8 slot in order to work properly.

2. Type: x4 PCI Express 2 x16

3. but the framegrabber is not working properly (it is highly unstable).

4. The tech support from Active Silicon has told us that the framegrabber should work properly in the x16 PCI Express 3 slot because of the backward compatibility that this slot should offer.

5. Now, I have read in the DELL discussion forums that this is not necessarily true: I mean, that this backward compatibility depends on the type of DELL machine that you are using.

6. Could you please tell us if the Optiplex 7070 MT offers this backward compatibility on the PCI Express x16 3.0 slots?

7. If not, how can we overcome this problem? should the motherboard be replaced or we need to use another DELL machine?

 

 

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1. You should probably write that as: PCIe v2.0 x8 slot (and "x8 electrical" aka Using 8-lanes)

2. Not sure what that means. Check OptiPlex 7070 MT PDF manual carefully.

3. If it works at all, it's not likely the slot.
- What version of Windows?
- What video-card?
- Is all other hardware well-above minimum system requirements?
- Have you tried a clean-install of Windows (without any Dell programs running in background)
- Capturing to the locally-installed (and very fast) NVMe-SSD
- Etc

4. Yes, a card that requires: PCIe v2.0 x8 slot (and "x8 electrical" aka Using 8-lanes)
should work fine in a: PCIe v3.0 x16 slot, either wired as "x16 electrical" aka Using 16-lanes
(or even wired as "x8 electrical" ) since that's all it really needs.

5. Those are all old-machines. Yours is fairly new. Also, yours is a (appropriate) tower-model and finally a 70xx OptiPlex is near the top of the series matrix.

6. See #4 above. Backwards compatibility is built-into the PCIe-specification. Maybe the machine is malfunctioning?

7. If this is for business I might suggest you bring-in a local experienced computer technician or consultant to help you.

Hello Thallium,

Thanks for your answer and sorry for such a late reply.

Yes, as you suggested, we tested the framegrabber in a optiplex 7010 and it works fine. We suppose that

this happens because the Optiplex 7010 Q77 chipset offers PCIe backward compatibility and the Optiplex 7070 TM  Q370 Chipset does not. But, ¿How can we be certain that this is true?

Kind regards.

Hello Tesla1856,

Here in our business, we purchased to Optiplex 7070 MT, and in both of them are experiencing the same problem.

We are not using a video card, but an Active Silicon framegrabber:

https://www.activesilicon.com/products/firebird-coaxpress-frame-grabber-dual-cxp-6/

We tested, this framegrabber in a DELL Optiplex 7010 MT and it works fine.

We think that maybe the problem is related to the machine's chipset:

- The DELL Optiplex 7010 MT Q77 chipset:  

https://ark.intel.com/content/www/us/en/ark/products/64027/intel-q77-express-chipset.html

offers something known as PCIe backward compatibility, but the

- The DELL Optiplex 7070 MT Q370  chipset: 

 https://ark.intel.com/content/www/us/en/ark/products/133282/intel-q370-chipset.html

does not.

Any help is welcomed,

Kind regards,

amattag

Hello @amattag , you may want to check out the Dell Precision 5820.  It's modern newer machine but you can manually set the PCIe link speed to gen 2.  If you have access to US markets, you can get an off lease or refurbished system for as little as 200 USD. 

Hello @Chino de Oro !

We tested the framegrabber in Dell Precision 7920 and it works fine.

The problem is that Dell Precision workstations are way up our approved budget here in Spain.

Kind regards.

Hello @Chino de Oro ,

"you can manually set the PCIe link speed to gen 2"

How can you do this?

Kind regards,

amattag

Hello @amattag , here is the option to manually select link speed in BIOS settings

That picture was for the Precision 5820, not the Optiplex 7070. That option is not in the Optiplex BIOS.