This is a split board - You can return to the Split List for other boards.

GTX 780 Overclocked beats R9 290X Overclocked. Dealbreaker for you?

#31DarkZV2BetaPosted 10/27/2013 7:03:10 PM(edited)
Bazooka_Penguin posted...
DarkZV2Beta posted...
Bazooka_Penguin posted...
DarkZV2Beta posted...
Bazooka_Penguin posted...
The 290x isn't aggressively overclocked out of box. AMD's new boost basically works like this. There's a target frequency (the max) and it clocks down towards a minimum frequency to compensate for heat. In other words, it's underclocking.

It's the opposite of Nvidia's boost with Kepler, which starts at a base frequency (a floor) and overclocks towards a max speed (the boost target) and then overclocks even more if the TDP allows it (Kepler boost).

Oh, and Gibbo on OCUK said he got his 290x to 1200+mhz on air


I bet it works exactly the same internally, though. Boost speed is actually just a show variable in the bios, and doesn't make any impact on operation.


Well it will once the 290x gets custom coolers. It's not going to continue boosting like Nvidia's kepler cards


nVidia's cards all have a maximum boost as set by voltage, though, as well as a long boost table with a frequency that can only be hit at 1.345v. This is crossreferenced with the maximum allowed voltage to determine maximum clock.(which only goes up to 1.212v, gen 1 Kepler is usually set at 1.163v, which limits it to 1.175v, gen2 kepler is set at I think 1.2v or 1.87v and can be unlocked to 1.212 in software)
Ultimately, the base clock only serves as a floor that it can't throttle below, and I'm pretty sure the "offset" is factored in separately. So a kepler card won't "keep boosting" on a better cooler. It'll just hit it's maximum clockspeed more often.

So essentially, AMD displays a different number(maximum frequency) and calculates offset a different way, and might even factor in voltage differently,(via voltage offset like MSI does for TOV?) but most likely, it's internally very similar.


The difference is that Nvidia's cards don't have an hard ceiling for the kepler boost. Kepler boost is (very conservatively) determined by the aforementioned parameters, not a hard limit, so if an individual chip can it will boost as high as it can for the given parameters. But 1000mhz is a hard limit, so even if the particular 290x chip could boost higher at a given voltage, temperature, and/or power limit it won't ever go over that limit; you'd have to OC it manually at that point. Nvidia's boost, as far as we know, is better than AMD's.


It is determined by a hard limit, though. The only difference is that AMD is displaying a particular variable in the boost table that the card can't go past, no different than the peak kepler boost for the card, instead of the base clock. Kepler boost will not continue to boost past that peak clock unless you manually unlock the voltage, which just raises it to another clockspeed in that table, and another hard limit.
The boost table for Kepler cards is even calculated from the maximum value. It doesn't overclock from the base value, it throttles from the maximum value, with a hard limit at the base value.
For safety reasons, it won't allow the card to operate above a certain voltage, but the logic behind it is still throttling from the set peak value.

Hell, with boost 2.0, I'm pretty sure you can even turn off the base value and allow it to throttle right to the minimum value in the table.
And for that matter, there's even a value within the bios to control maximum allowed boost besides voltage. AMD's boost can be perfectly replicated with Kepler Boost parameters and logic.
---
Want that Shield!
Ball and Cup on ps mobile has framerate issues. -stargazer64
#32DiehardFFv2Posted 10/27/2013 6:32:16 PM
MasterDonGero posted...
Dude, you can't make any errors in a post that is criticizing someone's language skills.


Damn, I missed a single space.
---
Intel i5 3570k | Sapphire r9 280x | 8GB DDR3 | 256GB SSD | 3TB HDD
#33overkillwfo1978Posted 10/27/2013 6:37:32 PM
One thing is steering me away from the 290X. High temps. Don't care if the card was meant to be run @ 95C... just too warm for me to consider. Especially as I would want to crossfire them eventually and having 2 super hot cards in one case doesn't sound like a good plan. Now, my options are single 780SC with option to SLI later, SLI 4gb 770s or crossfire 280X. Waiting to see if prices come down around black friday to pull the trigger.
---
"If you can't beat them, arrange to have them beaten" -George Carlin
#34Flaktrooper123Posted 10/27/2013 7:34:18 PM
Linus said that they actually tune down the fan until it hits 95. Maybe they are aware that their cooling solution is so dang loud. Regardless, I'll wait for non-reference.