6990's and risers - actual experiences?

[amazingrando]

I'm building some rigs with 6990's.  I have been told different things by different people.  One person has said that you cannot use risers with the 6990's because they draw too much power (even if using the molex powered version), while another person has said that you don't want them directly connected to the PCI slots (e.g. 3 x 6990s on an MSI 890FXA-GD70) or you will cause problems from heat or something.

For those of you who are running multiple 6990's per rig, what have you found? Are risers (powered or not) at all problematic?

[rjk]

The main thing that I have found is that the risers themselves tend to be rather fragile. While they are flexible and will bend, it is best to avoid much bending or twisting at all.

While I do not use 6990s, I believe that it is actually correct that 5870s (which I use) pull more power from the PCIe slot itself than 6990s do. Reason being that the 6990s have 8 pin power connectors and use them to the fullest advantage.

[amazingrando]

The main thing that I have found is that the risers themselves tend to be rather fragile. While they are flexible and will bend, it is best to avoid much bending or twisting at all.

While I do not use 6990s, I believe that it is actually correct that 5870s (which I use) pull more power from the PCIe slot itself than 6990s do. Reason being that the 6990s have 8 pin power connectors and use them to the fullest advantage.

I run a lot of 5870's with unpowered risers without a problem on a variety of motherboards.  Hmmm.

[drakahn]

-----
They shouldn't draw more than 75watts from the slot right?
and all pci-e slots are 75w
some motherboards 'share' wattage between slots, so if you try to take 75w from all slots it burns out, but thats what the molex is for right?
------
i don't have actual experience, i have risers on the way for 5970's which use less power i think so someone with actual experience still needs to pipe up

[amazingrando]

2x 6990s in one rig has not been a problem for me. also in the rig was a 5850.

Powered or unpowered risers?  What mobo?

[tnkflx]

I'm building some rigs with 6990's.  I have been told different things by different people.  One person has said that you cannot use risers with the 6990's because they draw too much power (even if using the molex powered version), while another person has said that you don't want them directly connected to the PCI slots (e.g. 3 x 6990s on an MSI 890FXA-GD70) or you will cause problems from heat or something.

For those of you who are running multiple 6990's per rig, what have you found? Are risers (powered or not) at all problematic?

Running a 8 GPU, 4x 6990 rig. Here are my findings:
- Windows 7 64bit with cgminer.
- I'm using 4 molex powered 16x risers without problems. They came from Cablesaurus.
- Power is split over 2 PSUs also with cables from Cablesaurus.
- I had to disable various motherboard components in the BIOS (esata, USB 3, ...), otherwise the 4th card wouldn't be recognized.

Rig has been running stable for the last 4-5 months.

Any questions? Shoot... ;-)

[amazingrando]

Running a 8 GPU, 4x 6990 rig. Here are my findings:
- Windows 7 64bit with cgminer.
- I'm using 4 molex powered 16x risers without problems. They came from Cablesaurus.
- Power is split over 2 PSUs also with cables from Cablesaurus.
- I had to disable various motherboard components in the BIOS (esata, USB 3, ...), otherwise the 4th card wouldn't be recognized.

Rig has been running stable for the last 4-5 months.

Any questions? Shoot... ;-)

Thanks for the info.  What are you using for a mobo and PSU?

[tnkflx]

Running a 8 GPU, 4x 6990 rig. Here are my findings:
- Windows 7 64bit with cgminer.
- I'm using 4 molex powered 16x risers without problems. They came from Cablesaurus.
- Power is split over 2 PSUs also with cables from Cablesaurus.
- I had to disable various motherboard components in the BIOS (esata, USB 3, ...), otherwise the 4th card wouldn't be recognized.

Rig has been running stable for the last 4-5 months.

Any questions? Shoot... ;-)

Thanks for the info.  What are you using for a mobo and PSU?

Motherboard: Gigabyte GA-990FXA-UD7.
PSU: 2x 1200W Modular ANTEC High Current Pro HCP-1200.

[amazingrando]

Running a 8 GPU, 4x 6990 rig. Here are my findings:
- Windows 7 64bit with cgminer.
- I'm using 4 molex powered 16x risers without problems. They came from Cablesaurus.
- Power is split over 2 PSUs also with cables from Cablesaurus.
- I had to disable various motherboard components in the BIOS (esata, USB 3, ...), otherwise the 4th card wouldn't be recognized.

Rig has been running stable for the last 4-5 months.

Any questions? Shoot... ;-)

Thanks for the info.  What are you using for a mobo and PSU?

Motherboard: Gigabyte GA-990FXA-UD7.
PSU: 2x 1200W Modular ANTEC High Current Pro HCP-1200.

Thanks.  I was considering almost exactly the same setup.

What do you do for cooling?  I'm guessing this is an open air rig?

[tnkflx]

Running a 8 GPU, 4x 6990 rig. Here are my findings:
- Windows 7 64bit with cgminer.
- I'm using 4 molex powered 16x risers without problems. They came from Cablesaurus.
- Power is split over 2 PSUs also with cables from Cablesaurus.
- I had to disable various motherboard components in the BIOS (esata, USB 3, ...), otherwise the 4th card wouldn't be recognized.

Rig has been running stable for the last 4-5 months.

Any questions? Shoot... ;-)

Thanks for the info.  What are you using for a mobo and PSU?

Motherboard: Gigabyte GA-990FXA-UD7.
PSU: 2x 1200W Modular ANTEC High Current Pro HCP-1200.

Thanks.  I was considering almost exactly the same setup.

What do you do for cooling?  I'm guessing this is an open air rig?

Yes, completely open. Cards are spaced approx. 1 inch apart...

[amazingrando]

Motherboard: Gigabyte GA-990FXA-UD7.
PSU: 2x 1200W Modular ANTEC High Current Pro HCP-1200.

Thanks.  I was considering almost exactly the same setup.

What do you do for cooling?  I'm guessing this is an open air rig?

Yes, completely open. Cards are spaced approx. 1 inch apart...

Do you have any extra fans either in front or behind?  How are temps?  Just trying to figure out if having four next to each other creates some kind of heat issues

[tnkflx]

Code:

--------------------------------------------------------------------------------
 [P]ool management [G]PU management [S]ettings [D]isplay options [Q]uit
 GPU 0:  74.0C 4278RPM | 404.4/405.1Mh/s | A:9375 R:40 HW:0 U: 5.55/m I: 9
 GPU 1:  77.5C 4909RPM | 400.2/402.1Mh/s | A:9440 R:33 HW:0 U: 5.59/m I: 9
 GPU 2:  79.0C 4772RPM | 401.2/398.6Mh/s | A:9495 R:36 HW:0 U: 5.62/m I: 9
 GPU 3:  77.5C 4783RPM | 374.0/372.6Mh/s | A:8657 R:34 HW:0 U: 5.12/m I: 9
 GPU 4:  77.5C  85%    | 370.1/371.0Mh/s | A:8622 R:33 HW:0 U: 5.10/m I: 9
 GPU 5:  77.5C  85%    | 389.7/375.7Mh/s | A:8755 R:31 HW:0 U: 5.18/m I: 9
 GPU 6:  73.0C   1%    | 383.4/387.7Mh/s | A:9076 R:36 HW:0 U: 5.37/m I: 9
 GPU 7:  76.0C  85%    | 362.3/370.6Mh/s | A:8773 R:25 HW:0 U: 5.19/m I: 9
--------------------------------------------------------------------------------

I mostly let cgminer manage everything.

[amazingrando]

Code:

--------------------------------------------------------------------------------
 [P]ool management [G]PU management [S]ettings [D]isplay options [Q]uit
 GPU 0:  74.0C 4278RPM | 404.4/405.1Mh/s | A:9375 R:40 HW:0 U: 5.55/m I: 9
 GPU 1:  77.5C 4909RPM | 400.2/402.1Mh/s | A:9440 R:33 HW:0 U: 5.59/m I: 9
 GPU 2:  79.0C 4772RPM | 401.2/398.6Mh/s | A:9495 R:36 HW:0 U: 5.62/m I: 9
 GPU 3:  77.5C 4783RPM | 374.0/372.6Mh/s | A:8657 R:34 HW:0 U: 5.12/m I: 9
 GPU 4:  77.5C  85%    | 370.1/371.0Mh/s | A:8622 R:33 HW:0 U: 5.10/m I: 9
 GPU 5:  77.5C  85%    | 389.7/375.7Mh/s | A:8755 R:31 HW:0 U: 5.18/m I: 9
 GPU 6:  73.0C   1%    | 383.4/387.7Mh/s | A:9076 R:36 HW:0 U: 5.37/m I: 9
 GPU 7:  76.0C  85%    | 362.3/370.6Mh/s | A:8773 R:25 HW:0 U: 5.19/m I: 9
--------------------------------------------------------------------------------

I mostly let cgminer manage everything.

Very helpful.  I use cgminer also, so it's really nice to see actual output.  I thought I read that I 5 was the best intensity setting.  Have you found that 9 is best?

[rjk]

Very helpful.  I use cgminer also, so it's really nice to see actual output.  I thought I read that I 5 was the best intensity setting.  Have you found that 9 is best?

5 maybe if its your desktop and you use it at the same time, otherwise 9 for a dedicated rig (8 if on p2pool).

[tnkflx]

Very helpful.  I use cgminer also, so it's really nice to see actual output.  I thought I read that I 5 was the best intensity setting.  Have you found that 9 is best?

5 maybe if its your desktop and you use it at the same time, otherwise 9 for a dedicated rig (8 if on p2pool).

Indeed ;-)

[amazingrando]

Very helpful.  I use cgminer also, so it's really nice to see actual output.  I thought I read that I 5 was the best intensity setting.  Have you found that 9 is best?

5 maybe if its your desktop and you use it at the same time, otherwise 9 for a dedicated rig (8 if on p2pool).

Awesome, thanks

[sunbreak]

I have 3x6990's on an MSI 890FXA-FD70 ... no risers, no power bypass.

System did 2630 mhash/sec in the 1.175 volt setting and pulled 1460 watts at the wall ... actually had to step it back because I kept hitting 1500 watts. Plus this was a 1200 watt PSU and although it performed this way for a month I've since decided the extra power wasn't worth it.

So at 1.12 volts and -125 memdiff the system ran 2520 mhash/sec @ 1170 watts (95 watts system) for 356 watts per card.

Flashing the 1.175 volt bios with 1.12 volt a 150 mhz memclock reduced the power by 150 watts for 1020 watts or 306 watts per card.

[tnkflx]

Flashing the 1.175 volt bios with 1.12 volt a 150 mhz memclock reduced the power by 150 watts for 1020 watts or 306 watts per card.

Any additional information about this?

[amazingrando]

I have 3x6990's on an MSI 890FXA-FD70 ... no risers, no power bypass.

System did 2630 mhash/sec in the 1.175 volt setting and pulled 1460 watts at the wall ... actually had to step it back because I kept hitting 1500 watts. Plus this was a 1200 watt PSU and although it performed this way for a month I've since decided the extra power wasn't worth it.

So at 1.12 volts and -125 memdiff the system ran 2520 mhash/sec @ 1170 watts (95 watts system) for 356 watts per card.

Flashing the 1.175 volt bios with 1.12 volt a 150 mhz memclock reduced the power by 150 watts for 1020 watts or 306 watts per card.

Are you running your memclocks at 150MHz or core clock minus 150?  Anything less than 300Mhz (at least on the 58xx series) definitely impairs performance.