Do AMD Radeon HD 4xxx cards use 2D/3D clocks?

[Stonedofmoo]

Can any Radeon owners let me know if their cards use different 2D/3D clocks, especially HD4770 owners.

Just curious as Nvidia do this on many of their cards, but I never see mention of it on AMD boards.

Cheers

 

[Clairvoyant]

Yes

 

[CaptainRAVE]

Yup, AMD still use it on all their cards (except when the drivers break its functionality).

 

[Meaker]

Only core clocks since the mem causes flashes when it changes clocks.

 

[finite]

Its a shame they couldn't crack that issue with the GDDR5 it kind of negates the power savings of the 40nm GPU on idle.

I read that card bios can also affect PowerPlay support, but I was looking at the 4670 there.

 

[Stonedofmoo]

Its a shame they couldn't crack that issue with the GDDR5 it kind of negates the power savings of the 40nm GPU on idle.

I read that card bios can also affect PowerPlay support, but I was looking at the 4670 there.

Aye, I've seen idle readings on the HD4770 and thats what made me question it. They were higher than the 55nm GTS250..

So basically if the memory were also to downclock the idle consumption would be awesome, but for now it's only the core that downclocks.

 

[gurusan]

memory frequency changes does very little (practically nothing whatsoever) for power consumption. It won't draw much current at all unless under load.

 

[roadie]

That's not true. My system with a 4890 drew over 20W less from the wall when the memory was down clocked to its minimum in CCC on the desktop.

If you want a card with low idle power consumption, it's best to avoid the GDDR5 based cards unless you are willing to manually down clock the memory when not gaming.

 

[gurusan]

best to avoid gddr5? It's the most power efficient memory available....

there is no way downclocking memory made a 20w diff. total bs

 

[craig3000]

Yes just use the catalyst control center or GPU-Z to see if it downclock automatically, it should do

 

[roadie]

Buy a power meter and check for yourself.

Also, a word of advice. I'd avoid making statements like that if you don't have the proof to back it up.

 

[roadie]

--

 

[Stonedofmoo]

there is no way downclocking memory made a 20w diff. total bs

According to this article, it does make a difference. This site saved 10w of power by downclocking the HD4770 memory to from 800Mhz to 450Mhz. Roadie has a more powerful HD4980 so it's sound entirely feasible he could save 20w by downclocking the memory on that.

Only in idle mode the power consumption seems to be a little high. Other Radeon cards show how to do it right. Apparently the reason for this result is still the high frequency of the GDDR5 video memory - since the clock speed is not reduced if the card is running in idle mode but stays at 800 MHz. So the chip internal buffers have to run with four times the frequency. If the clock speed is manually set to 450 MHz the power consumption is reduced to slightly above 20 watt.

http://www.pcgameshardware.com/aid,...s-HD-4850-und-Geforce-9800-GT/Reviews/?page=2

 

[gurusan]

indeed, looks like I was wrong. Seems totally ridiculous though?