GDDR5 is pretty amazing stuff!

[SlowSpyder]

I just ran CCC auto-tune on my 4870. This card is pre-overclocked from the factory at 780/1000 on the core/memory. I let auto-tune find my overclocks with the default dynamic fan speed adjustment (didn't set the fan to a fixed speed) on my Sapphire 4870 512MB Toxic edition card. It topped out at 1190MHz on the memory (810MHz on the core... nothing special, but not too shabby either). I kept waiting for it to stop, but it just kept on creeping higher and higher.

Anyone know how reliable the auto-tune feature is? Can I assume these clocks are safe to use?

Anyway, I thought getting the equivalent of 4760MHz on the memory was pretty impressive!

 

[thilanliyan]

Test using a bunch of games and furmark...then you'll know if it's stable. I wouldn't leave it solely up to auto-tune.

 

[SlitheryDee]

Originally posted by: SlowSpyder
I just ran CCC auto-tune on my 4870. This card is pre-overclocked from the factory at 780/1000 on the core/memory. I let auto-tune find my overclocks with the default dynamic fan speed adjustment (didn't set the fan to a fixed speed) on my Sapphire 4870 512MB Toxic edition card. It topped out at 1190MHz on the memory (810MHz on the core... nothing special, but not too shabby either). I kept waiting for it to stop, but it just kept on creeping higher and higher.

Anyone know how reliable the auto-tune feature is? Can I assume these clocks are safe to use?

Anyway, I thought getting the equivalent of 4760MHz on the memory was pretty impressive!

I just used it today, and my first impression is "not very". Auto tune pushed my gpu clock to 855 and the memory clock to 910. I loaded up Crysis Warhead to stress test it a bit and immediately noticed artifacts which got really bad after about a minute or so. I exited to the desktop and manually set the clocks back to stock and loaded the game again. Still artifacting. After double checking the clock speed with gpu-z I was freaking out a bit thinking auto-tune might have fried my card, but rebooting my computer seemed to solve the problem. That's something to remember, the clocks apparently don't revert back to stock until you reboot even though CCC and GPU-z will show the clocks you set.

I also had gpu-z log its sensor readings for a while when I was running the game and I noticed that the fan speed never went above 50% while the card was overclocked and obviously overheating. I thought this might be an error on GPU-Z's part but after the reboot set my computer to rights the fan noise was noticeably louder and gpu-z started registering fan speeds above 50%. Kind of a strange glitch there. I haven't had the nerve to fool with auto-tune again to see if it recurs.

BTW I have a 4870 1gb.

 

[error8]

Never use autotune again. That program doesn't know what it's doing! It's upping the clocks like there is no tomorrow, without being able to do a serious stability test. You might find your ram to be games stable at 1020 mhz or so, even if autotune brought it almost to 1200mhz.

Always use the classic overclock method. That never fails and has very little chance of damaging your card.

 

[kylebisme]

Originally posted by: SlitheryDee
I loaded up Crysis Warhead to stress test it a bit and immediately noticed artifacts which got really bad after about a minute or so. I exited to the desktop and manually set the clocks back to stock and loaded the game again. Still artifacting. After double checking the clock speed with gpu-z I was freaking out a bit thinking auto-tune might have fried my card, but rebooting my computer seemed to solve the problem.That's something to remember, the clocks apparently don't revert back to stock until you reboot even though CCC and GPU-z will show the clocks you set.

Actually, what happened is; the card got too hot while it was overclocked, and rebooting gave it some time to cool off.

 

[SlowSpyder]

Ah, so much for auto-tune. I figured nothing is ever easy. Who knows, maybe my memory doesn't like nearly as high of a clock as I thought. Guess I'll find out later.... looks like I have some old fashioned trial and error testing to do.

 

[videogames101]

I maxed out CCC's clock speed on core and memory, still solid as a rock, no auto-tune. (Rig below)


(65% fan)