5870 memory speed without causing crashes

[chungenhung]

Lowered the 5870 memory to 300MHz. Windows is showing funny pictures. However, it is hashing just fine.
What are your experiences when it comes to 5870 memory speeds? What speed is stable, which version driver? OS?

[1714818703]

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[Eveofwar]

When you say "funny pictures"...do they look similar to little purple or green blocks ?  If so...sounds like GPU artifacts :/

New or used card ?  If used, sounds like it's been overworked.

http://www.lmgtfy.com/?q=gpu+artifacts

[chungenhung]

When you say "funny pictures"...do they look similar to little purple or green blocks ?  If so...sounds like GPU artifacts :/

New or used card ?  If used, sounds like it's been overworked.

http://www.lmgtfy.com/?q=gpu+artifacts

Comon, don't use that lmgtfy on me.
Yes, they are artifacts, but they only occur when the 5870's memory are lowered.
The monitor is connected to a 5830.
5830 and 5870 are working fine together if 5870's memory is at default, no artifacts.
It starts to artifact is if I lower the 5870 memory by flashing BIOS.
Artifacts don't appear if I use Sapphire Trixx to lower it.
I've read somewhere that it has to do with Windows trying to set the memory speed when it enters the desktop. That is why using Trixx to lower it AFTER it has entered the desktop would not cause artifacts.

[DeathAndTaxes]

Don't try flashing bios.  Just use cgminer.  I run 5970s (almost the same card GPU wise) at 190 Mhz w/o issue. 

Really no reason to use that Trixx garbage or deal w/ custom bioses.  Just use cgminer and be done with it.

[Eveofwar]

When you say "funny pictures"...do they look similar to little purple or green blocks ?  If so...sounds like GPU artifacts :/

New or used card ?  If used, sounds like it's been overworked.

http://www.lmgtfy.com/?q=gpu+artifacts

Comon, don't use that lmgtfy on me.
Yes, they are artifacts, but they only occur when the 5870's memory are lowered.
The monitor is connected to a 5830.
5830 and 5870 are working fine together if 5870's memory is at default, no artifacts.
It starts to artifact is if I lower the 5870 memory by flashing BIOS.
Artifacts don't appear if I use Sapphire Trixx to lower it.
I've read somewhere that it has to do with Windows trying to set the memory speed when it enters the desktop. That is why using Trixx to lower it AFTER it has entered the desktop would not cause artifacts.

Posted lmgtfy to give you google references...not to insult

Interesting that you would see artifacts on the 5830, if the 5870 is the "suspect"...I was under the impression that artifacts are supplied from the card that the monitor is attached to.

[DeathAndTaxes]

Interesting that you would see artifacts on the 5830, if the 5870 is the "suspect"...I was under the impression that artifacts are supplied from the card that the monitor is attached to.

I didn't catch that in first reading of it.  Yeah weird the 5830 would show distortion from the unused card.   You aren't by any chance using dummy plugs or or expanding the desktop to the 5870 or other silliness are you?

[chungenhung]

No dummy plugs, no extending desktop.
I am trying to install the latest driver now.

[ZodiacDragon84]

noob question, isn't higher memory a good thing?

[DeathAndTaxes]

noob question, isn't higher memory a good thing?

No.  Bitcoin requires negligible memory or bandwidth.  Higher memory tends not to improve performance but uses power and produces heat.  Sometimes lowering memory can actually slightly improve performance but the main reason is to reduce heat/power and alllow higher overclocking of core.

The best GPU for mining would be a quad 5870 on only a PCIe 1x slot w/ a couple MB of memory to reduce cost.   I doubt AMD will build that one though. 

[ZodiacDragon84]

Thank  DnT. I had mine clocked all the way up (sheepish dumb grin) Gonna go remedy that right now.

Edit: Added about 50Mhash/s on one of my 5870s, other got about 13Mhash/s improvement. Clocks on both running 900Mhz, Memory at overdrive minimum of 900Mhz. Thanks again DnT

[Eveofwar]

Thank  DnT. I had mine clocked all the way up (sheepish dumb grin) Gonna go remedy that right now.

Edit: Added about 50Mhash/s on one of my 5870s, other got about 13Mhash/s improvement. Clocks on both running 900Mhz, Memory at overdrive minimum of 900Mhz. Thanks again DnT

Use ATI Tray Tools and set memory to 1/3rd your GPU clock speed

[ZodiacDragon84]

Thank  DnT. I had mine clocked all the way up (sheepish dumb grin) Gonna go remedy that right now.

Edit: Added about 50Mhash/s on one of my 5870s, other got about 13Mhash/s improvement. Clocks on both running 900Mhz, Memory at overdrive minimum of 900Mhz. Thanks again DnT

Use ATI Tray Tools and set memory to 1/3rd your GPU clock speed

Im pulling 385 Mhash/s and 390 Mhash/s with Bitminter Pools Java Software. No need to get so crazy on my hardware yet...lol

[tiberiandusk]

I run all my cards at 300mhz memory. If I go lower it affects my hashrate and stability.

[rjk]

I run all my cards at 300mhz memory. If I go lower it affects my hashrate and stability.

I discovered this recently - was trying to OC to 950 on a 5870 at 150 memory, and the machine kept freezing, even though the temps were fine etc. When I put the memory back to 300, it got nice and stable again.

[sadpandatech]

I run all my cards at 300mhz memory. If I go lower it affects my hashrate and stability.

I discovered this recently - was trying to OC to 950 on a 5870 at 150 memory, and the machine kept freezing, even though the temps were fine etc. When I put the memory back to 300, it got nice and stable again.

aye, I agree on the memory thing. it is possible to go too low. On my 5830's clocked at 1020GPU they seem most stable at ~345 mem. This seems to vary a bit based on which card models, mem bandwidth, gpu OC and the work size being used.

It's been a while since I was testing any of that but it seemed to somewhat coincide with what the total memory % being used on the cards were. I.e., at too low mem Mhz the memory usage would get up clost to 50% and the issue seemed to start at about that point. Though, other than just casual observation of it I've no way to know if it was the actual cause or not.

cheers

TL;DR start at ~600mem and work your way down 50 at a time until you find it unstable. Then bump it back up by 10 or so at a time until you find your sweet spot.

[P4man]

No problems with memory at 300 Mhz on any of my 5850s or 5870. Havent tried any lower.
Funny thing, I do have artifacting at 400 Mhz (and it works fine again at 900 Mh and 1 GHz  ).

If you are mining under windows; do a few things:
-disable windows 7 aero theme
-disable flash acceleration in your browser; otherwise any flash or youtube clip is likely to corrupt or crash your desktop.
-use cgminer and do not use ati ccc to control your clocks. In fact, dont even install ccc.

[jake262144]

... or better yet, just disable Windows

[Turbor]

No problems with memory at 300 Mhz on any of my 5850s or 5870. Havent tried any lower.
Funny thing, I do have artifacting at 400 Mhz (and it works fine again at 900 Mh and 1 GHz  ).

I run my 5850s at 200 (dummy plug) and 280 MHz. At 400 the artifacts force you to restart. Temperature wise there is no difference between 300 MHz and 200 MHz. At least with my setup.

[chungenhung]

... or better yet, just disable Windows

by that you mean just switch to Linux?

[jake262144]

... or better yet, just disable Windows

by that you mean just switch to Linux?

Naturally.