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Topic: Lowering mem clock to idle speeds SPEEDS UP Mh/s (Read 39026 times)

sr. member
Activity: 418
Merit: 250
Naturally, memory clock wouldn't affect the hashes produced. This is not the memories job to provide calculations. The only thing you benefit from by lowering mem clocks is significant heat reduction produced by your gpu. Also, you may get more stale shares if you're in a pool as your gpu is taking that much longer to process and it tends to miss the last bit or so of a calculation. This is what generally causes a stale/invalid share (false information due to gpu leaving out a bit or two of info).

In my experience, lower mem clock to about 300 Mhz for a relatively stable experience. Doesn't cause too many invalid shares and may reduce your temp by about 8 degrees Celsius depending on your card.

Good sir, I do say you're quite skilled in the art of Talking Out Your Ass.

Reading your paragraph reminds me of when a woman goes to a mechanic, "he said my muffler bearings were going out, blinker fluid was low, and I somehow made it to the shop with only one transmission and need the second one put back in asap!"
legendary
Activity: 1708
Merit: 1020
Naturally, memory clock wouldn't affect the hashes produced. This is not the memories job to provide calculations. The only thing you benefit from by lowering mem clocks is significant heat reduction produced by your gpu. Also, you may get more stale shares if you're in a pool as your gpu is taking that much longer to process and it tends to miss the last bit or so of a calculation. This is what generally causes a stale/invalid share (false information due to gpu leaving out a bit or two of info).

In my experience, lower mem clock to about 300 Mhz for a relatively stable experience. Doesn't cause too many invalid shares and may reduce your temp by about 8 degrees Celsius depending on your card.
I am interested into anything that might help to reduce stales. Going up from 269 to 400 did not seem to result in less stales. I will run some more tests.
full member
Activity: 302
Merit: 100
Presale is live!
... Also, you may get more stale shares if you're in a pool as your gpu is taking that much longer to process and it tends to miss the last bit or so of a calculation. This is what generally causes a stale/invalid share (false information due to gpu leaving out a bit or two of info).
...

Don't spread bullshit like that, reducing the clock of GDDR ram, ram or any type of chip wouldn't make it "leave out a bit or two" (a FPGA or ASIC might do due to timeing issues but that would moste likely make it fail completly)
Secondly even if it did leave out bits the different mining applications are very unlikely to even accept them as shares and thus report them to the pool...
full member
Activity: 168
Merit: 100
Naturally, memory clock wouldn't affect the hashes produced. This is not the memories job to provide calculations. The only thing you benefit from by lowering mem clocks is significant heat reduction produced by your gpu. Also, you may get more stale shares if you're in a pool as your gpu is taking that much longer to process and it tends to miss the last bit or so of a calculation. This is what generally causes a stale/invalid share (false information due to gpu leaving out a bit or two of info).

In my experience, lower mem clock to about 300 Mhz for a relatively stable experience. Doesn't cause too many invalid shares and may reduce your temp by about 8 degrees Celsius depending on your card.
legendary
Activity: 1855
Merit: 1016
If you're using Windows Check out: http://forum.bitcoin.org/index.php?topic=9982

I have EAH5850s and was not able to under clock under 500MHz with MSI Afterburner, but with Clocktweak I can under clock down to 175MHz.  I get 311Mh/s @ 825/175 and temps are between 55-59C. 
You have to enable over clocking in MSI Afterburner. Then only it will let you go below 500 & also u have to go 500, exit Afterburner & open again, now reduce further.

Thanks for the clock tweak link.

newbie
Activity: 2
Merit: 0
If you're using Windows Check out: http://forum.bitcoin.org/index.php?topic=9982

I have EAH5850s and was not able to under clock under 500MHz with MSI Afterburner, but with Clocktweak I can under clock down to 175MHz.  I get 311Mh/s @ 825/175 and temps are between 55-59C. 
legendary
Activity: 1855
Merit: 1016
Thanks PcChip, that worked like a charm! I should've mentioned I was using a sapphire card in my orig. post.

Sapphire users, check out TriXX, it seems to work better on our cards than the oft-recommended MSI Afterburner. No need to mess with ATI driver install, the default standard set is fine.

>300Mh/s, 5830 @ 996/300. Custom fan control keeps it around 65C, which I think is acceptable for long term use.

Sapphire Trixx doesn't show more than one card details like Afterburner shows.
I have 2 sapphire cards & 2 Asus cards & the BEST OC software in windows is MSI Afterburner.
I already tried & tired with Asus pc doctor, sapphire Trixx, AMD GPU clock tool, AMD over drive.......
newbie
Activity: 20
Merit: 0
Thanks PcChip, that worked like a charm! I should've mentioned I was using a sapphire card in my orig. post.

Sapphire users, check out TriXX, it seems to work better on our cards than the oft-recommended MSI Afterburner. No need to mess with ATI driver install, the default standard set is fine.

>300Mh/s, 5830 @ 996/300. Custom fan control keeps it around 65C, which I think is acceptable for long term use.
legendary
Activity: 1526
Merit: 1002
Waves | 3PHMaGNeTJfqFfD4xuctgKdoxLX188QM8na
It works great!

I just started mining (BTCmine pool) yesterday with my new X2 255 (under-volted/clocked tot 1.1volt and 2.4Ghz) and an Asus EAH5770 GPU.

GPU 899Mhz / 1,160 volt
300 Mhz mem
197Mhash/s

Power consumption: 170Watt.

full member
Activity: 139
Merit: 100
6870
Memory: 357
Core: 1025
Hashing: 314,36MH/s

Windows 7 x64
Catalyst 11.5

phoenix -u http://:@:/ -k phatk VECTORS BFI_INT FASTLOOP=false DEVICE=0 AGGRESSION=11
full member
Activity: 139
Merit: 100
Great advice, thank you.
newbie
Activity: 35
Merit: 0
Thought I'd post my results on underclocking memory.

I run an ASUS 4870 DK using poclbm -w 256 -f 60.
Trying the clocking around I got to ~92.5 MH/s @ 830 core and 900-300 memory using MSI Afterburner.
After trying to go lower I started to see a hash boost when going below 250. Going lower, I found that @ 173 and lower my card immediately froze, and less than 185 it would crash and do a VPU reset after a small time.
But at 190 is a sweet spot for me. Hashing increased by 2-3 MH/s compared to anything above 250, and as a bonus the card runs a lot cooler, practically flatlining at 61 degrees at the moment.
It is also pretty effective, pulling that by only using 85w over when sitting idle, or about 1.1 MH/J.

http://imageshack.us/photo/my-images/196/unled1yxj.jpg/

I'm a happy new miner.  Cheesy

Edit: Pumping core up to 840, my card sits pretty stable at 95.7 MH/s and 62 degrees. Using -w 256 -f 10 makes me go up to 98.4, though windows becomes sluggish then.
I can run at 850 core and get 100 MH/s, but at that point if I so much as touches anything that causes extra GUI operations, the drivers crash.
Before when I clocked core to 850 with standard memory clocks, the card would crash instantly, even when not running the miner. So underclocking memory is a great success I'd say.
sr. member
Activity: 686
Merit: 259
Using pocplm with an HD5770 (-v -w128), no matter what I get maximum hashes at default memory clock (1200). If I lower it at 300, I get like 5 MHash/s less..
EDIT: Who says the truth?

Reason is very simple. You have installed the express version of catalyst driver, which even if you not selected AMD overdrive to OC, controls the clocking ability & it completely denies & don't allow to hash more, even though you are lowering mem clock & it is shown in Afterburner & also in Overdrive.
AMD overdrive controls the mem clock in background which you can't see.

Simple solution, Uninstall all the catalyst driver using driver sweeper & then reinstall using latest or any catalyst driver with CUSTOM install & install only these 3, ATI display driver, ATI catalyst install manager, APP 2.4.

Check this, http://forum.bitcoin.org/index.php?topic=6458.msg168021#msg168021
Lowering mem clock reduces temp up to 10C & also increases hash rate.
If you have 6870 card use these, mem clk = (core clk/3) + 14.
If you have 5870 card use these, mem clk = core clk/3.

This gives the MAXIMUM hash with MINIMUM temperature.
Perfect, perfect and perfect!
Now I don't get any hash/s loss, and the temperature reduced.
I did these things
1) Uninstall AMD Overdrive
2) Use Driver Sweeper and clean all ATI drivers
3) Reboot in Safe mode
4) Run Driver Sweeper again in Safemode
5) Install ATI 11.5 using only the 3 selected things you told me.

Still, I can't know at which temperature is my GPU.

If you uninstalled everything & installed only the 3 i said, you won't have AMD VISION Engine Control Center (it is the catalyst center which blocks UC of memory). Just run the setup again & select uninstall & uninstall Catalyst control center.


In your picture,in Afterburner even though fan speed says 68%, fan tachometer, RPM says 0, means fan is not running or may be fan connector fault.
Remove dust from fan to reduce temp.
Also,in Afterburner set fan speed in to manual instead of AUTO & slide it to 100% & see whether temp drops or not.
Unistalled AMD Vision and all the not needed things. I get the same MH/s as before, so it seems that CCC wasn't the problem.
Also, MSI Afterburner says that fan rpm are 0, but if I put it to 100% I hear a fucking noise, so it is working Cheesy
I'm still getting high temps btw.
There isn't dust in the fan, so the problem must be another. Could it be the thermal paste? Or the plastic cover made by ASUS?
sr. member
Activity: 418
Merit: 250
I had the exact same problem, install TriXX 4.0.1

also, in a multi-card rig with only one monitor, you can only change the clocks of the card the monitor is connected to at the moment (unless you use dummy plugs)
legendary
Activity: 1855
Merit: 1016
Until u try, u can't see problems or solutions.
Seeing post is NOT trying practical.
Install only 3, & if you still can't lower mem clk, then i accept 5830 won't allow to go mem clk below 650.
If you look at overdrive, core clk & mem clk when not mining, it will be in 300 & 300 only.
newbie
Activity: 20
Merit: 0
Trying to lower memory clocks on my 5830 below 650 is giving me instant blank screens with vertical blue lines, seemingly these speeds are not accepted by my hardware. I've tried 600, 500, 300, all with the same problem. Moving from 800/1000 (stock speed) to 950/650 has been rock stable but i'd like to drop it the memory clock farther if it will save me temp, energy and probably card life. Anyone else have this problem?

I saw the posts about completely removing drivers and reinstalling a limited set, but I haven't had trouble changing clocks until I try to apply mem clocks 600Mhz or less... so I don't think its a problem with the ATI drivers interfering.
legendary
Activity: 1855
Merit: 1016
Using pocplm with an HD5770 (-v -w128), no matter what I get maximum hashes at default memory clock (1200). If I lower it at 300, I get like 5 MHash/s less..
EDIT: Who says the truth?

Reason is very simple. You have installed the express version of catalyst driver, which even if you not selected AMD overdrive to OC, controls the clocking ability & it completely denies & don't allow to hash more, even though you are lowering mem clock & it is shown in Afterburner & also in Overdrive.
AMD overdrive controls the mem clock in background which you can't see.

Simple solution, Uninstall all the catalyst driver using driver sweeper & then reinstall using latest or any catalyst driver with CUSTOM install & install only these 3, ATI display driver, ATI catalyst install manager, APP 2.4.

Check this, http://forum.bitcoin.org/index.php?topic=6458.msg168021#msg168021
Lowering mem clock reduces temp up to 10C & also increases hash rate.
If you have 6870 card use these, mem clk = (core clk/3) + 14.
If you have 5870 card use these, mem clk = core clk/3.

This gives the MAXIMUM hash with MINIMUM temperature.
Perfect, perfect and perfect!
Now I don't get any hash/s loss, and the temperature reduced.
I did these things
1) Uninstall AMD Overdrive
2) Use Driver Sweeper and clean all ATI drivers
3) Reboot in Safe mode
4) Run Driver Sweeper again in Safemode
5) Install ATI 11.5 using only the 3 selected things you told me.

Still, I can't know at which temperature is my GPU.

If you uninstalled everything & installed only the 3 i said, you won't have AMD VISION Engine Control Center (it is the catalyst center which blocks UC of memory). Just run the setup again & select uninstall & uninstall Catalyst control center.


In your picture,in Afterburner even though fan speed says 68%, fan tachometer, RPM says 0, means fan is not running or may be fan connector fault.
Remove dust from fan to reduce temp.
Also,in Afterburner set fan speed in to manual instead of AUTO & slide it to 100% & see whether temp drops or not.
legendary
Activity: 1855
Merit: 1016
I have 2 asus EAH5870 & 1 sappire HD 5870 for my SH rig & every card is mining at 430+ Mhash/s with 975 core clk & 325 mem clk in windows 7 32 bit, with aero enabled.
It seems to depends on the card, not the card model.
For my 5870 GPU is set to 900 (it's unstable for higher values) and the performance does not change more than 1% within the range 175<=MEM<=900. Thus I've set 175 for energy & noise reasons.
full member
Activity: 211
Merit: 100
It seems to depends on the card, not the card model.
For my 5870 GPU is set to 900 (it's unstable for higher values) and the performance does not change more than 1% within the range 175<=MEM<=900. Thus I've set 175 for energy & noise reasons.
sr. member
Activity: 686
Merit: 259
Using pocplm with an HD5770 (-v -w128), no matter what I get maximum hashes at default memory clock (1200). If I lower it at 300, I get like 5 MHash/s less..
EDIT: Who says the truth?

Reason is very simple. You have installed the express version of catalyst driver, which even if you not selected AMD overdrive to OC, controls the clocking ability & it completely denies & don't allow to hash more, even though you are lowering mem clock & it is shown in Afterburner & also in Overdrive.
AMD overdrive controls the mem clock in background which you can't see.

Simple solution, Uninstall all the catalyst driver using driver sweeper & then reinstall using latest or any catalyst driver with CUSTOM install & install only these 3, ATI display driver, ATI catalyst install manager, APP 2.4.

Check this, http://forum.bitcoin.org/index.php?topic=6458.msg168021#msg168021
Lowering mem clock reduces temp up to 10C & also increases hash rate.
If you have 6870 card use these, mem clk = (core clk/3) + 14.
If you have 5870 card use these, mem clk = core clk/3.

This gives the MAXIMUM hash with MINIMUM temperature.
Perfect, perfect and perfect!
Now I don't get any hash/s loss, and the temperature reduced.
I did these things
1) Uninstall AMD Overdrive
2) Use Driver Sweeper and clean all ATI drivers
3) Reboot in Safe mode
4) Run Driver Sweeper again in Safemode
5) Install ATI 11.5 using only the 3 selected things you told me.

Still, I can't know at which temperature is my GPU.
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