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Recently I went from 4850 1gb - > 6950 crossfire.
Systematically specs:
Corsair hx-850w
Athlon II x4 640 stock at 3.0ghz
Patriot g2 16gb 1333mhz
Foxconn A7DA-S 3.0 AM3 790gx (2x PCI-E x16)
2x reference design AMD 6950 2gb
4.5 tb of disk space all 7200 across 3 separate disks
1 dvd rw drive
1 fan controller
4 case fans
ZALMAN CNPS9900MAX cpu cooler (1 fan)
When I received my two 6950's I tested each one individually and then tried them together in crossfire.
They each worked fine except for one dvi port on the second card not working, which I knew about at the time of purchase (which btw anyone have a fix?)(I was thinking bios issue).
Each card worked fine for an hour on prime 95 and in various pc games.
However both cards in conjunction would not even boot to Windows. And the pc would reset and give me a Hypertransport Sync Flood Error. I tried lowering the ht speed in the bios and the nb would not allow me to go above a x16 speed. I would reset the bios. Tried more voltage to each component and nothing still worked.
I have tested each component individually on my fm1 based htpc and everything works great. I was obviously unable to test the cpu and motherboard because of socket differences.
Htpc specs:
Asrock a75 pro4-m (has 2 pcie slots but I haven't the slightest clue what the 2nd runs at)
AMD FM1 3870k 3.0 GHz quad.
4gb 1600mhz ddr3
Rocket fish cm 212 copy cooler
Seagate 1 tb 5900 rpm drive
I obviously had to use my hx-850w because the 430 in the htpc was insufficient.
Also there was no fans aside from psu, cpu cooler, and 1 on each graphics card because I am bread boarding because the cards are long than the matx htpc case.
Crossfire was stable for an hour with the 4gb ram and is stable for 1 hour and counting with my 16gb.
I did not install my gfx card drivers on the htpc windows because I did not want to clean them afterwards.
II also tried to install a clean windows on a spare drive in my gaming rig and got numerous bsod after copying windows files.
So everything has been tested besides cpu and motherboard and I don't think my psu is overloaded.
II can hook up my kill a watt to my gaming rig if someone thinks it will be helpful but the htpc with my 2 cards is pulling 100 at idle and 180 in prime 95.
If I had to guess I would say it is my motherboard but I want some more input.
My reasons for this are:
I can overvolt my cpu and it changes nothing
My htpc cpu is undervolted by quite a lot (I shaved 80w off of the load power)
I previously had trouble with my motherboard not knowing to choose igp or 4850 before a 4850 bios update (required me to turn the pc off once the fan reached 100%, then turn it back on while the fans were spinning, really strange)
Systematically specs:
Corsair hx-850w
Athlon II x4 640 stock at 3.0ghz
Patriot g2 16gb 1333mhz
Foxconn A7DA-S 3.0 AM3 790gx (2x PCI-E x16)
2x reference design AMD 6950 2gb
4.5 tb of disk space all 7200 across 3 separate disks
1 dvd rw drive
1 fan controller
4 case fans
ZALMAN CNPS9900MAX cpu cooler (1 fan)
When I received my two 6950's I tested each one individually and then tried them together in crossfire.
They each worked fine except for one dvi port on the second card not working, which I knew about at the time of purchase (which btw anyone have a fix?)(I was thinking bios issue).
Each card worked fine for an hour on prime 95 and in various pc games.
However both cards in conjunction would not even boot to Windows. And the pc would reset and give me a Hypertransport Sync Flood Error. I tried lowering the ht speed in the bios and the nb would not allow me to go above a x16 speed. I would reset the bios. Tried more voltage to each component and nothing still worked.
I have tested each component individually on my fm1 based htpc and everything works great. I was obviously unable to test the cpu and motherboard because of socket differences.
Htpc specs:
Asrock a75 pro4-m (has 2 pcie slots but I haven't the slightest clue what the 2nd runs at)
AMD FM1 3870k 3.0 GHz quad.
4gb 1600mhz ddr3
Rocket fish cm 212 copy cooler
Seagate 1 tb 5900 rpm drive
I obviously had to use my hx-850w because the 430 in the htpc was insufficient.
Also there was no fans aside from psu, cpu cooler, and 1 on each graphics card because I am bread boarding because the cards are long than the matx htpc case.
Crossfire was stable for an hour with the 4gb ram and is stable for 1 hour and counting with my 16gb.
I did not install my gfx card drivers on the htpc windows because I did not want to clean them afterwards.
II also tried to install a clean windows on a spare drive in my gaming rig and got numerous bsod after copying windows files.
So everything has been tested besides cpu and motherboard and I don't think my psu is overloaded.
II can hook up my kill a watt to my gaming rig if someone thinks it will be helpful but the htpc with my 2 cards is pulling 100 at idle and 180 in prime 95.
If I had to guess I would say it is my motherboard but I want some more input.
My reasons for this are:
I can overvolt my cpu and it changes nothing
My htpc cpu is undervolted by quite a lot (I shaved 80w off of the load power)
I previously had trouble with my motherboard not knowing to choose igp or 4850 before a 4850 bios update (required me to turn the pc off once the fan reached 100%, then turn it back on while the fans were spinning, really strange)