7950 GPU usage jumping up and down on scrypt

[glon]

I'm close to crying right now, as I could not get my hd7870 past 300KH previously and now I've sold it and bought a HD7950 that, besides only pusing 400KH, seems to be exhibiting this weird issue:

GPU usage jumping up and down between 100 and 64% while scrypt mining in CGminer. I'm not even overclocked yet, just testing the card at these settings:

--thread-concurrency 8192 -I 12 -g 2 -w 256 --verbose



Anyone seen this before and knows what's going on?

Many thanks for any replies!

[balanghai]

Seems to me a configuration problem if not over temperature.

Mostly the problem lies on the memory clock, you need to fine tune it to a point it's pretty much stable. Your vantage point is when you can do other things while hashing at the same time. Keep us posted.

[glon]

OK this is weird. Found a solution in another thread and it works for me:

I can resolve this problem just by set the power limit around 10-20%

What exactly does the "power limit" setting do?

[hendo420]

Try this instead.

--thread-concurrency 8192 -I 19 -g 1 -w 256 --verbose

in my experience -g 2 -I 13 is only for 7970s

Download Gpu-z and check your vrm temp, if it gets over 95c it will cause ur gpu to throttle, I dont see that being the problem as your card is around 60c.

You may be pulling more power than your psu can put out. What wattage is your PSU?

I think you are talking about powertune. I keep mine from 10-15 depending on the card.

[glon]

Try this instead.

--thread-concurrency 8192 -I 19 -g 1 -w 256 --verbose

in my experience -g 2 -I 13 is only for 7970s

Download Gpu-z and check your vrm temp, if it gets over 95c it will cause ur gpu to throttle, I dont see that being the problem as your card is around 60c.

You may be pulling more power than your psu can put out. What wattage is your PSU?

I think you are talking about powertune. I keep mine from 10-15 depending on the card.

Hi,

--thread-concurrency 8192 -I 19 -g 1 -w 256 --verbose

is giving me only 350KH but I'm still on default clocks. My PSU is a 500W Seasonic, the whole rig is not drawing more than 300W at wall while mining.

What next? Overclock, or should I be looking into the low KHs on default clocks first?

[FiiNALiZE]

Try this instead.

--thread-concurrency 8192 -I 19 -g 1 -w 256 --verbose

in my experience -g 2 -I 13 is only for 7970s

Download Gpu-z and check your vrm temp, if it gets over 95c it will cause ur gpu to throttle, I dont see that being the problem as your card is around 60c.

You may be pulling more power than your psu can put out. What wattage is your PSU?

I think you are talking about powertune. I keep mine from 10-15 depending on the card.

Hi,

--thread-concurrency 8192 -I 19 -g 1 -w 256 --verbose

is giving me only 350KH but I'm still on default clocks. My PSU is a 500W Seasonic, the whole rig is not drawing more than 300W at wall while mining.

What next? Overclock, or should I be looking into the low KHs on default clocks first?

Try -I 13 and -g 2

I own both 7970s and 7950s and that usually works for me.

[glon]

Try this instead.

--thread-concurrency 8192 -I 19 -g 1 -w 256 --verbose

in my experience -g 2 -I 13 is only for 7970s

Download Gpu-z and check your vrm temp, if it gets over 95c it will cause ur gpu to throttle, I dont see that being the problem as your card is around 60c.

You may be pulling more power than your psu can put out. What wattage is your PSU?

I think you are talking about powertune. I keep mine from 10-15 depending on the card.

Hi,

--thread-concurrency 8192 -I 19 -g 1 -w 256 --verbose

is giving me only 350KH but I'm still on default clocks. My PSU is a 500W Seasonic, the whole rig is not drawing more than 300W at wall while mining.

What next? Overclock, or should I be looking into the low KHs on default clocks first?

Try -I 13 and -g 2

I own both 7970s and 7950s and that usually works for me.

Same 350KH result with this setting, but maybe it's OK for a 7950 on default clocks?

[Tranz]

OK this is weird. Found a solution in another thread and it works for me:

I can resolve this problem just by set the power limit around 10-20%

What exactly does the "power limit" setting do?

Yes up the power limit. It allows the GPU to gt more power when it needs it. If you don't do this the only thing the GPU can do is slow down, which you are seeing.

7950 should hit at least 500khs with no OC.

[FiiNALiZE]

It seems that your card is throttling but since your temps + PSU are fine, that's out of the question.

I did a bit of research and found that some other people have issues with their 7950 as well.

I see that your default core clock is 925mhz. That's the default clock for the Boost Bios:

http://www.techpowerup.com/reviews/AMD/HD_7950_Boost_BIOS_Upgrade/

Basically this BIOS version automatically adjusts your GPU's core clock in real time, which accounts for the fluctuations.

If I were you, I would flash my BIOS to an older version without the Boost upgrade and see if that fixes the problem.

Good luck

[glon]

It seems that your card is throttling but since your temps + PSU are fine, that's out of the question.

I did a bit of research and found that some other people have issues with their 7950 as well.

I see that your default core clock is 925mhz. That's the default clock for the Boost Bios:

http://www.techpowerup.com/reviews/AMD/HD_7950_Boost_BIOS_Upgrade/

Basically this BIOS version automatically adjusts your GPU's core clock in real time, which accounts for the fluctuations.

If I were you, I would flash my BIOS to an older version without the Boost upgrade and see if that fixes the problem.

Good luck

The fluctuations issue I've already solved by upping the "power limit" setting from 0 to 20.

Still the best I can do is 410KH, even overclocked to 1060/1450, with these settings:

--thread-concurrency 21712   -I 19  -g 1 -w 256 --verbose

Anything else and my KHs goes below 400.. WTF is wrong with these cards?

[FiiNALiZE]

It seems that your card is throttling but since your temps + PSU are fine, that's out of the question.

I did a bit of research and found that some other people have issues with their 7950 as well.

I see that your default core clock is 925mhz. That's the default clock for the Boost Bios:

http://www.techpowerup.com/reviews/AMD/HD_7950_Boost_BIOS_Upgrade/

Basically this BIOS version automatically adjusts your GPU's core clock in real time, which accounts for the fluctuations.

If I were you, I would flash my BIOS to an older version without the Boost upgrade and see if that fixes the problem.

Good luck

The fluctuations issue I've already solved by upping the "power limit" setting from 0 to 20.

Still I can't get the card above 400KH and I'm already overclocked to 1060/1450

Exactly.

Read the article about the Boost Bios.

Powertune is tied with Boost. Powertune can only go to a max of 20%, so of course upping it to 20 will make your card stable.

I'm not sure if flashing your BIOS to an older version will increase your hashrate, but it seems like a good idea.


Also, look at the graph at the end of this article:

http://www.pcper.com/reviews/Graphics-Cards/AMD-Radeon-HD-7950-3GB-PowerTune-Boost-Review

Looks a lot like yours.

[cannonfodder]

The fluctuations issue I've already solved by upping the "power limit" setting from 0 to 20.

Still I can't get the card above 400KH and I'm already overclocked to 1060/1450

This setting gets me 620Kh/s:

OC 1090/1600 powertune @ 10

--intensity 18 --thread-concurrency 24000 -w 128

[glon]

The fluctuations issue I've already solved by upping the "power limit" setting from 0 to 20.

Still I can't get the card above 400KH and I'm already overclocked to 1060/1450

This setting gets me 620Kh/s:

OC 1090/1600 powertune @ 10

--intensity 18 --thread-concurrency 24000 -w 128

This gives me 450KH.

Now, using

--intensity 18 --thread-concurrency 24000 -w 256

instead, gives 410KH so apparently changing the work unit value is the way to go for me, so thanks for that at least.

[cannonfodder]

The fluctuations issue I've already solved by upping the "power limit" setting from 0 to 20.

Still I can't get the card above 400KH and I'm already overclocked to 1060/1450

This setting gets me 620Kh/s:

OC 1090/1600 powertune @ 10

--intensity 18 --thread-concurrency 24000 -w 128

This gives me 450KH.

Now, using

--intensity 18 --thread-concurrency 24000 -w 256

instead, gives 410KH so apparently changing the work unit value is the way to go for me, so thanks for that at least.

No problem. Unfortunately every make of card has it's own quirks, so keep trying different settings and good luck. What make is yours? Mine are Sapphire.

[glon]

The fluctuations issue I've already solved by upping the "power limit" setting from 0 to 20.

Still I can't get the card above 400KH and I'm already overclocked to 1060/1450

This setting gets me 620Kh/s:

OC 1090/1600 powertune @ 10

--intensity 18 --thread-concurrency 24000 -w 128

This gives me 450KH.

Now, using

--intensity 18 --thread-concurrency 24000 -w 256

instead, gives 410KH so apparently changing the work unit value is the way to go for me, so thanks for that at least.

No problem. Unfortunately every make of card has it's own quirks, so keep trying different settings and good luck. What make is yours? Mine are Sapphire.

Mine's Sapphire too. There goes your theory. Just kidding.

[cannonfodder]

Mine's Sapphire too. There goes your theory. Just kidding.

Hmm. Did you enable unofficial overclocking via MSI Afterburner?

[glon]

Yes, and I'm using MSI Afternurner to OC the card. I'm using Afterburner also because apparently OCing via CGminer commands does not work for me. i.e. putting in something like

--gpu-memclock 1000 --gpu-engine 1450

does not increase either clock at all. Now that I think about it, could this be a hint as to what might actually be wrong?

[cannonfodder]

Yes, and I'm using MSI Afternurner to OC the card. I'm using Afterburner also because apparently OCing via CGminer commands does not work for me. i.e. putting in something like

--gpu-memclock 1000 --gpu-engine 1450

does not increase either clock at all. Now that I think about it, could this be a hint as to what might actually be wrong?

I don't know. I unlocked the overclocking via afterburner, but then used Sapphire's Trixx for the OC and undervolting since afterburner wasn't undervolting for some reason.

[glon]

OK guys, I feel so stupid now. Turns out I was editing one batch file and launching a different one (via a desktop shocrut) all this time. OMG, I know.

That also explains why Ocing via cgminer did nothing to the card. Now getting 500KH on stock clocks so it seems I am good to go.

Thanks a lot and sorry about this.

[cannonfodder]

  At least you figured out what was happening.