Geforce GTX 680 review -
The graphics architecture that is Kepler
The graphics architecture that is Kepler
As you can understand, the massive memory partitions, bus-width and combination of GDDR5 memory (quad data rate) allow the GPU to work with a very high framebuffer bandwidth (effective). Let's again put most of the data in a chart to get an idea and better overview of changes:
|Graphics card||GeForce GTX 480||GeForce GTX 580||GeForce GTX 680|
|Streaming Multiprocessors (SM)||15||16||8|
|Graphics Clock (Core)||700 MHz||772 MHz||1006/1058 MHz|
|Shader Processor Clock||1401 MHz||1544 MHz||1006/1058 MHz|
|Memory Clock / Data rate||924 MHz / 3696 MHz||1000 MHz / 4000 MHz||1502 MHz / 6008 MHz|
|Graphics memory||1536 MB||1536 MB||2048 MB|
|Memory bandwidth||177 GB/s||192 GB/s||192 GB/s|
|Power connectors||1x6-pin PEG, 1x8-pin PEG||1x6-pin PEG, 1x8-pin PEG||2x6-pin PEG|
|Max board power (TDP)||250 Watts||244 Watts||170 Watts|
|Recommended Power supply||600 Watts||600 Watts||550 Watts|
|GPU Thermal Threshold||105 degrees C||97 degrees C||98 degrees C|
So we talked about the core clocks, specifications and memory partitions. Obviously there's a lot more to talk through.
To understand a graphics processor you simply need to break it down into pieces to better understand it. Let's first look at the raw data that most of you can understand and grasp. This bit will be about the Kepler architecture, if you're not interested in g33k talk by all means please browse to the next page.
So above we see the GK104 block diagram that entails the Kepler architecture. Let's break it down into bits and pieces. The GK104 will have:
- 1536 CUDA processors (Shader cores)
- 192 CUDA core clusters (SM).
- 8 geometry units
- 4 raster Units
- 128 Texture Units
- 32 ROP engines
- 256-bit GDDR5 memory bus
- DirectX 11.1
The more important thing to focus on are the SM (block of shader processors) clusters (or SMX as NVIDIA likes to call it for the GTX 680, which has 192 Shader processors. That's radically different from Fermi, the GeForce GTX 580 for example had 32 shader processors per SM cluster. 1536 : 192 = 8 Shader clusters (SMs). Let's blow up one such cluster:
Above the block diagram for a single Shader processor cluster, aka SM or SMX as NVIDIA now calls it. The new SMX has quite a bit more bite in terms of shader, texture and geometry processing. 192 CUDA cores, that's six times the number of cores per SM opposed to Fermi. Now, at the end of the pipeline we run into the ROP (Raster Operation) engine and the GTX 680 again has 32 engines for features like pixel blending and AA.
There's a total of 128 texture filtering units available for the GeForce GTX 680. The math is simple here, each SM has 16 texture units tied to it.
- GeForce GTX 580 has 16 SMs X 4 Texture units = 64
- GeForce GTX 680 has 8 SMs X 16 Texture units = 128
Above the GK104 host interface - The Gigathread engine, four GPCs, four memory controllers, the ROP partitions, a 768 KB L2 cache. Each GPC has eight polymorph engines - ROP partitions are nearby to the L2 cache, Each shader cluster then is tied to L1 and a shared L2 cache. Shading performance is going be increased quite bit, geometry performance will get a nice boost as well.
NVIDIA is using 64KB Shared Memory/L1 per SMX please note that they have a 16/48 48/16 ratio here for graphics/compute, as before with Fermi. For L2, 128KB per 64-bit memory controller. So that adds up to 512KB L2
In regards to architectural changes, on top of the pipeline NVIDIA has now added new Polymorph 2.0 (world space processing) engines and raster (screen space processing) engines, they act like a mini CPU really.
We test and review the ASUS GeForce GTX 780 DirectCU II review edition. The graphics card comes with a factory overclock and an updated DirectCU II cooler that has CoolTech fans. That would be two silent 90mm fans.
MSI GeForce GTX 770 Lightning review
In this review we benchmark the MSI GeForce GTX 770 Lightning edition. Armed with military class components, an awesome TwinFrozr cooler that is very silent and keeps this GPU chilled down at a cool 60 Degrees C temperature. Next to that is has voltage monitoring points, a reactor core, a secondary BIOS as backup and liquid cooling and well, just so much more. Have a peek at what might be one of the finest GeForce GTX 770 cards available on the market.
EVGA GeForce GTX 770 SC review
In this review we peek at the EVGA GeForce GTX 770 SC (SuperClocked) edition. This model graphics card comes with a factory overclock and the new ACX cooler. Overall the card is sitting in-between the GeForce GTX 680 and GeForce GTX 780 , with its 1111 MHz core clock frequency. We take the latest games and do some FCAT testing as well.
Win a Palit GeForce GTX 770 JetStream graphics card
Guru3D and Palit once again partner up to get you some cool hardware. Palit this week released the GeForce GTX 770 JetStream edition graphics card which offers high-end performance whilst being totally silent. To participate, all you need to do is Like our Facebook page and comment in a thread as to why you need this card so much. Good Luck!