About a month ago I bought 2 Dell Optiplex 760 MTs. Both systems are exactly the same in every way and work very well. Both have the latest A16 BIOS and all the latest drivers from Dell installed.
Last week, I bought a Dodocool 2-port USB 3.0 PCIe expansion card and it works on both Optiplex 760 PCs when placed in either the PCIe x1 or x16 slots. HOWEVER...
On only one of the systems, it's a hit or miss as to whether the BIOS detects the card from a cold start up (the BIOS detects all the PCIe slots, just sometimes not this particular card - it will just show "empty", when it should say "USB").
As a result, if the BIOS doesn't detect the card, then it's not available in Windows when Windows loads in. Therefore, when I start the PC, I always have to enter the BIOS to see if the card is detected before windows boots.
If BIOS shows the card I just exit the BIOS and let the PC boot into Windows and all is fine.
But if the BIOS doesn't detect the card, I have to exit the BIOS, push the power button on the tower to shut the system off, then power on again and re-enter the BIOS and find that the card is recognized (sometimes might take 2 or 3 tries but many times only one try is sufficient).
It never happens if I simply do a restart from the OS. On a restart, the BIOS always remembers/sees/detects the card. It only happens if I do a shutdown and have to power-up the system using the power button on the tower.
This problem happens only with this one system and only with this particular PCIe card and not any other PCIe cards and it doesn't matter if it is installed in the PCIe x1 or PCIe x16 slot - the problem is the same. No problems on either PCIe slot with any other PCIe cards.
I have tried many many times to replicate this problem on the other identical PC but I cannot replicate it. The BIOS on the "good" PC detects this PCI card every single time.
At first I thought it was a defective mobo or defective PCIe x1 slot but when I saw that it also happens on the PCIe x16 slot and other PCIe cards I've tried get detected by the BIOS with no problems, I don't think I can conclude it is a bad mobo or slot(s).
I also don't see how it is a defective PCIe card since it works flawlessly on one system. In fact, it works on both systems, just that in one the BIOS might not detect it on just one of the PCs.
I'm hoping someone here can shed some light on this.
Here is a list of everything I have tried...
Flashed the BIOS 3 times now (A16 BIOS).
- Bade sure the card was seated properly every time.
Tested voltages both PSUs under load. Both systems' voltages tested out fine.
Ran the command "bcdedit /set CONFIGACCESSPOLICY DISALLOWMMCONFIG" in Safe Mode with command prompt. I did this because I read an old thread from another forum for a similar problem and this fixed that person's problem. But it did not fix my problem. Admitedly I am not quite sure what this command really is.
Reset the CMOS with the jumper and removed battery for several minutes.
Replaced CMOS battery with fresh one, even though the old one tested at 3.1v. New battery tests out at 3.2v.
- Used the RAM from the "good" PC on the "bad" PC. No change to situation
- Reinstalled (several times) the latest Renesas 201-202 USB driver for this card v184.108.40.206.
Both systems specs:
- Dell Optiplex 760 MT
- Nanya 6GB DDR2 PC2-6400 (800MHz) RAM
- Intel Core 2 Duo 3.0GHz E8400 CPU
- Dell Inc. 0M858N mobo
- Dell BIOS vA16
- Windows 7 Pro 64-bit SP1 (using on-board graphics for both)
I appreciate any help on this matter. It's driving me nuts! lol