Looking Down, Below the Cooling System

Had enough about the look and feel of the Calibre series? Well, then it's time to dig a bit deeper. Let's see what lies beneath the cooling system of the Sparkle Calibre 8800 GTX OC edition graphics accelerator. We are taking a look under the hood by pulling of the cooling solution. As you know by removing the cooling system you are voiding the warranty of your graphics card. So, only for those who don't care about the warranty and want to see what's underneath, with proper handling the heatsink can be removed for whatever reasons. However we don't recommend it, but at the same wanted to share the real stuff that makes the GTX what it is today.

After removing the screws, the heatsink can be taken off and the full scale PCB sees the light. What a difference; the heatsink itself covered almost completely the PCB, with the cooling system being a bit heavier than the PCB itself. Most electronic components have been invisible from the start on the front side of the PCB. Some smaller components were not covered by the heatsink, which are located close to the power connections. Oh yes, we forgot to mention the GTX needs quite a bit of power so it comes with dual 6-pin power connections. All other main components like the GPU, voltage regulators and memory chips however could only be seen once the cooling solution was taken off. Quite normal these days for any high-end graphics accelerator as cooling has become an important aspect.

The Sparkle Calibre 8800 GTX OC edition is powered by the new G80 series line of graphics processors. The G80 core used is physically the same chip as you will find back on the GeForce 8800 GTS video cards and features the unified shader technology, represented by the stream processors. The NVIDIA G80 chip uses a 90nm manufacturing process for its high performance circuits and has been designed from scratch around the unified shader logic. The GeForce 8800 GTX core works at 575MHz operation speed, actually a bit higher clocked than the GTS which is set at 500MHz. In practice the GTX runs at 576MHz core speeds, so a tiny bit higher than what the specifications detail. And the Calibre series do bring in some more, as these are clocked at 630MHz core speed.

	GeForce 8800 GTX	Calibre 8800 GTX
Core Speed	575MHz	630MHz
Memory Speed	1800MHz	1960MHz
Shader Clock	1350MHz	1350MHz
Stream Processors	128	128
Memory Size	768MB GDDR3	768MB GDDR3
Memory Interface	384-bit	384-bit
HDCP Support	Compliant	Compliant

With the introduction of the G80 core we see that a new era being kicked off which is all about the unified shader technology. To incorporate this within the GeForce 8800 series we see that NVIDIA has come up with the stream processors which can be used in a unified way as either vertex or pixel shader. That means that these are no longer fixed to just being a vertex or pixel shader, but their function changes according to the processing needs. With a unified GPU architecture some bottleneck between pixel, shader and geometric processing is reduced to a great extend. These stream processors have their own speed setting, which is called the shader clock. For the Calibre 8800 GTX the shader clock is set at 1350MHz, but scalable up to 1500MHz according to the specifications.

The Sparkle Calibre 8800 GTX OC edition comes with twelve memory chips in total which are all located on the front side of the board. The memory chips are placed strategically around the G80 core. Each of these memory chips gives their heat away to the coolers aluminum sole via elastic rubber-like thermal pads. And as the Calibre series make use of a different cooling system, and extra black cooling plate was designed to efficiently reduce the heat produced. By cooling the memory chips on their own, it provides extra protection towards the lifetime of the chips in general. The ram chips are placed four by four by four and give a total of 768MB memory.

With 768MB GDDR3 memory the Sparkle Calibre 8800 GTX OC edition is well equipped for experiencing the full graphical power of current and upcoming gaming technology. It features Hynix branded GDDR3 memory which is running at 1.96GHz speed. These Hynix GDDR3 chips come marked as 1.0ns access time and are therefore rated at 2.0GHz frequency and operating at 2.2V. So what does that mean...no overclocking? Well, not at all as these Hynix memory chips can easily reach about 2.1GHz! And maybe even more. And these chips are known to go really fast, but these are currently the fastest GDDR3 memory around. If faster speeds need to be attained a move toward GDDR4 would be the only logical one to take which currently can reach speeds up to 2.8GHz.

The second chip next to the G80 controls input/output functions albeit slightly more advanced. This controller handles Transition Minimized Differential Signaling (TMDS) which is a feature that is very difficult to include in the core itself, particularly given how complex the G80 core already is. The NVIO controller also offers HDCP support which provides a robust, cost effective and transparent method for transmitting and receiving digital entertainment. The two dual link DVI ports on the Calibre 8800 GTX OC edition are driven by this new NVIDIA NVIO controller. Well that's about it on the insights of the Sparkle Calibre 8800 GTSX OC edition graphics card, so we will just reassemble it again, applying some new thermal compound and stick it into our test system.