Evga Geforce GTX 670 4GB Version Out

The GeForce GTX 670 review galore has started. In this review we'll look at a board from EVGA, it is the SC model that comes factory overclocked (a little). The GeForce GTX 670 is the little brother of the GTX 680 and comes well how to put it ... slightly castrated. NVIDIA disabled a couple of shader processors and designed a more cost effective and smaller PCB.

The card itself is still quite beefy in terms of performance though, which you'll understand once we sifted through the specifications. The GK104 GPU based graphics card has one SM/SMX cluster disabled. This gives the GK104 GPU 1344 CUDA cores to work with, with in total, 112 texture and 32 raster operating units.

The (reference) graphics card also has slightly slower clock frequencies than big poppa GTX 680, with a reference baseclock speed of 915 MHz. However the GTX 670 as well comes with a Boost clock which is set at 980 MHz -- not far off from the GTX 680 at all.

EVGA released a series of SKUs based on the GTX 670, amongst them you'll find these:

• EVGA GeForce GTX 670 2GB: $399.99
• EVGA GeForce GTX 670 2GB Superclocked: $419.99
• EVGA GeForce GTX 670 4GB: $469.99
• EVGA GeForce GTX 670 4GB Superclocked: $489.99

We have the 2GB SC edition in the house which comes pre-overclocked at 967 MHz on the baseclock and 1046 MHz on the boost clock. More interestingly. To give the card enough frame buffer to work with the cards are equipped with 2048 GDDR5 on a 256-bits wide bus. EVGA clocks this memory at 6210 MHz (effective data rate), which is slightly overclocked as well. As you have noticed there will be 4 GB model out soon as well, albeit we're not sure if the memory on these models will get a factory tweak. We can only recommend you 4GB version if you have a very high-resolution monitor and mod your games like Skyrim with extreme HQ texture packs. Otherwise 2GB is more than sufficient.

With a TDP at roughly 170 Watts the card won't draw too much power either. With that said you have the more important variables in your mindset.By: Hilbert Hagedoorn Edited by Eddy

We'll now look at the reference (original design) based specs and architecture. The GeForce GTX 670 is based on the new Kepler GPU architecture. It is based on the very same 28nm GK104 GPU which is used on the GeForce GTX 680.

The GeForce GTX 670 boasts 1344 CUDA (shader) cores whereas the GeForce GTX 680 has 1536 CUDA (shader) cores. That's 192 Shader cores less, and that's precisely one CUDA core clusters (SM) less out of the eight available. The product is obviously PCI-Express 3.0 ready and has a TDP of around 170 Watt (with a typical draw of 150~160W). But let me first show you GK104 die:

NVIDIA GK104 Kepler architecture GPU, you can see the eight SM (CUDA/shader core) clusters, one of these has been deactivated for the GTX 670.

An immediate difference to the GPU core versus the shader processor domain is that both will be clocked at 1:1, meaning both the core and shader domain clock in at 915 MHz. The boost clock for the reference GHTX 670 cards is set at 980 MHz though that can vary a bit per card and available power envelope (topping 1 GHz would not surprise me).

As far as the memory specs of the GK104 Kepler GPU are concerned, the boards will feature a 256-bit memory bus connected to 2 GB of GDDR5 video buffer memory. On the memory controller side of things you'll see very significant improvements as the reference memory clock is set at 6 GHz / Gbps. This boils down to to a memory bandwidth of 192 GB/s on that 256-bit memory bus.

With this release, NVIDIA now has the third product in the series 600 cards on its way. The new graphics adapters are of course DirectX 11.1 ready. With Windows 8, 7 and Vista also being DX11 ready all we need are more new games to take advantage of DirectCompute, multi-threading, hardware tessellation and the latest shader 5.0 extensions.

For your reference here's a quick overview of some past generation high-end GeForce cards opposed to the new Kepler based GeForce GTX 680.

	GeForce GTX 480	GeForce GTX 580	GeForce GTX 670	EVGA GTX 670 SC	GeForce GTX 680	GeForce GTX 690
Stream (Shader) Processors	480	512	1344	1344	1536	3072
Core Clock (MHz)	700	772	915	967	1006	915
Shader Clock (MHz)	1400	1544	-	-	-	-
Boost clock (Mhz)	-	-	980	1046	1058	1019
Memory Clock (effective MHz)	3700	4000	6080	6210	6080	6008
Memory amount	1536	1536	2048	2048	2048	4096
Memory Interface	384-bit	384-bit	256-bit	256-bit	256-bit	256-bit
Memory Type	GDDR5	GDDR5	GDDR5	GDDR5	GDDR5	GDDR5

For Kepler, NVIDIA kept their memory controllers GDDR5 compatible. Memory wise NVIDIA has nice large memory volumes due to their architecture, we pass 2 GB as standard these days for most of NVIDIA's series 600 graphics cards in the high range spectrum.

The hardware engineers of NVIDIA reworked the memory subs system quite a bit, enabling much higher memory clock frequency speeds compared to previous generation GeForce GPUs. The result is this memory speeds up-to 6 Gbps. Each memory partition utilizes one memory controller on the respective GPU, which will get 256/512 MB of memory tied to it.

• The GTX 580 has six memory controllers (6x256MB) = 1536 MB of GDDR5 memory
• The GTX 670 has four memory controllers (4x512MB) = 2048 MB of GDDR5 memory
• The GTX 680 has four memory controllers (4x512MB) = 2048 MB of GDDR5 memory

As mentioned in the introduction, a 4 GB version is going to be offered as well.