Thursday, March 8th 2012
GK104 Dynamic Clock Adjustment Detailed
With its GeForce Kepler family, at least the higher-end parts, NVIDIA will introduce what it calls Dynamic Clock Adjustment, which adjusts the clock speeds of the GPU below, and above the base-line clock speeds, depending on the load. The approach to this would be similar to how CPU vendors do it (Intel Turbo Boost and AMD Turbo Core). Turning down clock speeds under low loads is not new to discrete GPUs, however, going above the base-line dynamically, is.
There is quite some confusion regarding NVIDIA continuing to use "hot clocks" with GK104, the theory for and against the notion have been enforced by conflicting reports, however we now know that punters with both views were looking at it from a binary viewpoint. The new Dynamic Clock Adjustment is similar and complementary to "hot clocks", but differs in that Kepler GPUs come with a large number of power plans (dozens), and operate taking into account load, temperature, and power consumption.
The baseline core clock of GK104's implementation will be similar to that of the GeForce GTX 480: 705 MHz, which clocks down to 300 MHz when the load is lowest, and the geometric domain (de facto "core") will clock up to 950 MHz on high load. The CUDA core clock domain (de facto "CUDA cores"), will not maintain a level of synchrony with the "core". It will independently clock itself all the way up to 1411 MHz, when the load is at 100%.
Source:
VR-Zone
There is quite some confusion regarding NVIDIA continuing to use "hot clocks" with GK104, the theory for and against the notion have been enforced by conflicting reports, however we now know that punters with both views were looking at it from a binary viewpoint. The new Dynamic Clock Adjustment is similar and complementary to "hot clocks", but differs in that Kepler GPUs come with a large number of power plans (dozens), and operate taking into account load, temperature, and power consumption.
56 Comments on GK104 Dynamic Clock Adjustment Detailed
So if the situation is a very straight forward computation work and does not heat up the GPU at 700Mhz, it will overclock itself to say... 1000Mhz so that the task can be done more quickly while staying within the thermo-envelope.
Why not have it on previous GPU? I believe this type of thermo management requires additional hardware sensors built-in to monitor the GPU precisely and ensure that it does not get cooked. It can be done in software but the profile can't be as aggressive.
This is how Intel CPU works. I'm guessing that is how Kepler will work.
Bringing down speed to 300MHz might compel us to doubt the efficiency & reliability at higher speeds but I believe it really is a power saving feature rather than a way to mitigate any of Kepler's problems.
Again, lets hope for a competitive Kepler series rather than a below par one! Its good for us consumers.
this adds dozens, so now they have more than just a 2D or 3D state - now a low demanding game with Vsync on or an FPS cap, it simply wont use the same amount of power, heat and noise.
Hence you cannot exactly match the OC characteristics/capability of CPU and GPU but only compare to an extent on the basis of computational load.
the rest is on the firmware i guess, because each card behaves different much like CPU's, so the profiles must be set in the firmware on each card (and could be modified by the end user later)
this isnt off/2D/3D/OC, its going to have ten steps in between each of those.
lets say you fire up team fortress 2 and leave Vsync on: the card might only clock up to 30% of its total power to do so, and it will sit there, saving you power, heat, and noise.
so instead of running at 100% clocks and 30% load, it could now run at 30% clocks at 100% load, if that makes sense to you.
Simply lower clocks and introduce the clocks-performance level they were aiming for as a new "feature".
This is NOT like turbo, as that slows other unused cores down to maintain the same power envelope, it doesnt speed all cores up, what Intel and AMD call a overall faster chip is a new product name, not a feature.
Im just as confused, however, seeing yet another news bit, the TDP is 195W, substantially lower than the 7970, and faster?It was also mentioned/rumored that the turbo is only 7% of stock clocks. I mean, that nets you maybe a couple FPS, usually not the difference between playable and not, ya know? Im leaning on the side of pointless myself.
But to increase speed while under full load? Why not just have that full power available when needed, and just worry about the lower-load scenarios?
Admittedly I know probably less than you do, as GPUs really aren't my thing, so I was serious in that I am confused about this, and need more info, or a different way to explain why they are doing it this way.
And if anything, this relates to TSMC having issues...AMD and Nv seemingly have just chosen to deal with it differently. We know that the current 7-series cards have HUGE OC potential...to me it doesn't make sense that they didn't release those cards @ 1000 MHz and let the OEMs have 1100-1125 for OC editions...
I'm not saying what nV is doing is wrong, but that it's weird, and curious, and I'd like to know more.
Nvidia has historically failed to allow for much manufacturing error, meaning a substantially lower yield on new processes, and clock/heat issues resulting from it.
If you have a voltage drop of .2v in the core and you have a targeted speed of 1Ghz at 1.2vcore, you then have to run 1.4vcore to achieve your target numbers, but at a hugely increased thermal load. I am guessing this is Nvidias problem with this chip, but also why they have been able to beat AMD/ATI in performance per mm. How many threads about dead 8800's do we have due to heat issues? Lower the voltage and heat output and your competitive advantage dies when your clocks fall, and your yields suffer.
With this all said though, I think Kepler is going to be screaming fast, but how much more does your electricity bill have to be to gain that performance and is it worth using your computer as a mini-space heater?
If it were so much cooler they would have used a single slot cooler.
If it was so much faster they would be shouting it from the roof.
If it were available........but its not.
So here we are. Speculation about a feature that mah help fix a problem no one had or cared about, or just some media spin from marketing to generate some green fog in our brains.
Every time people bring up Nvidia cards they feel obligated to describe them as monsterous, hot, power-plant fueled alternatives to AMD's offerings. Clearly people care about Power Consumption, and heat is always an issue, so I have no idea what you're getting at there.
As for the possibility of a Single-Slot Cooler, who knows, but I'm well adjusted to not needing one. Usually only one or two AMD cards are specially designed by manufacturers to support single slot coolers, and those run pretty damn hot. It's just not cost-efficient these days. I don't see people complaining when AMD does it.
You're also forgetting the kicker, this was intended to be Nvidia's mid-range chip. They may not price it accordingly, but that was the original intent.