Hello all, i know a lot of you qre quite ATi tech savvy, so I though thtis to be the best place to ask. My 5870 has out of nowhere decided to underclock itself and will nto have me telling it otherwise. I tried setting it to overclocked speeds, and no go. I'm running Catalyst 9.12 under 64 bit Windows 7. Thank you for your thoughts. :)

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I'm not ATI tech savvy but I'll give you my thoughts anyway.
It's normal for them to clock down when they are idle, but I suppose you know that.

Catalyst Control Centre is limited to a maximum of 900 MHz core speed on most 5870 brands. If you try to use MSI Afterburner after unlocking it in the MSIAfterburner.cfg file, as soon as you adjust the core speed, it will automatically increase the memory speed to 940 MHz, which is higher than required for MilkyWay performance and just uses more power and produces extra heat than using a lower memory speed such as 500 MHz.

I use AMD GPU Clock Tool, which allows you to set the core and memory speed separately. Once you use it though PowerPlay downclocking on idle will no longer work and it will reset to default core speed if you reboot. On my Vapor-X 5870 I currently use 940/500 for MilkyWay and 940/1200 for Collatz.

As always when overclocking just increase in little steps and monitor your temps and stability each time before trying any higher speeds. Overclocking increases the risk of instability and potential card damage due to overheating. Although modest increases are usually OK if you haven't increased the voltage, keep in mind that MilkyWay stresses certain parts of the card much more than a tool such as FurMark. FurMark on a 5870 will give readings of 43A or so on VDDC, whereas MilkyWay can exceed 67A. That's a lot more current than FurMark which is considered to be a fairly rigorous stress test. So take care and check anything anyone tells you because overclocking is your own responsibility.

I'll try some third party tools, I just hadn't had time yet, and had not had this problem til very recently. I noticed my MW RAc was dropping like a rock, and lo and behold... at 99% usage the card was WAY underclocked. I know the dangers of overclocking, I just tried to in the CCC to try and get the card to kick up and go, but alas, it did nothing. Sadly I have to be off to work again, but will mess with it more over the holiday weekend, and more suggestions are greatly appreciated(not to downplay yours, for which I thank you).

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From what you have to say Zanth it sounds like the card for whatever reason isn't speeding up to 3d speeds when MW is running and is staying at the 2d desktop speeds.

I'd suggest uninstalling and re-installing the driver as something may not have installed correctly and it isn't detecting that it should go to 3d speeds. Or worst case uninstall the 9.12 and put the 9.11 back on if they were running properly as there may be some kind of issue with your setup and the 9.12 drivers.

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>I know the dangers of overclocking

I didn't mean to imply you had no knowledge of overclocking, it is just my responsibility if I have suggested a method to do so, to issue some kind of disclaimer and warning.

Most of the GPU overclocking information you see is done by those who test by running games or using short running stress tests. Crunching on the GPU however is continuous and high temperatures can build up in summer weather conditions. I had to run my 4890 with adjusted parameters because it overheated on default parameters. The 5870 cools very well due to the Vapor-X cooling but I still use a floor fan blowing into the side of the case when it's hot or the fan speeds up and is too noisy for my liking. It's not super noisy but just an annoying whining sound which is not good for sleeping.

Hope you find out what is causing your card to slow down.

My 5870 is not fully stable either, even at default speeds it crashed about every 2 days with either a blank screen or rebooted. I never saw it happen, it always did it when I was asleep. I've worked out it happens when I'm running either AQUA or projects that use a large amount of memory. The 4890 never crashed, no matter what project I ran on the CPU.

So this morning when I sit down to mess with my system, I look, and my 5870 is happily chugging along at the proper speeds, and my MW RAC is on the mend. No matter how much tech knowledge one can attain, computers will never fully be understood, I don't think. They really do seem to have minds of their own. Thanks for all the help and suggesstions guys, merry christmas!

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So this morning when I sit down to mess with my system, I look, and my 5870 is happily chugging along at the proper speeds, and my MW RAC is on the mend. No matter how much tech knowledge one can attain, computers will never fully be understood, I don't think. They really do seem to have minds of their own. Thanks for all the help and suggesstions guys, merry christmas!

>.<... Seriously, we don't need AI... Computers are temperamental enough already... Imagine what they would be like if they could think for themselves!!

Glad it all worked out though :) And Happy Holidays to you as well!

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Even though your problem seems to have disappeared, I thought I'd chip in and provide another, possible explanation. The 5800 series cards had an entirely reworked power system to provide low idle speeds/power usage and to protect against excessive power loads that were generated by stress testing apps like FurMark and OCCT. You can get more detailed into @ http://www.anandtech.com/video/showdoc.aspx?i=3643&p=11 start at paragraph 8 for the power management segment.

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