Design and Features
It’s hard to tell the new card apart from the MSI R7970 Lightning we tested earlier. It looks the same and even has the same dimensions (300x125x49 millimeters):
Contrasting with the black casing, the silvery logos of MSI, Twin Frozr IV and Lightning Series and the bright yellow stripes catch the eye, making the card attractive.
The N680GTX Lightning is equipped with two dual-link DVI outputs, one HDMI 1.4a and one DisplayPort 1.2:
The connectors are gold-plated, emphasizing the high status of the product. There are two MIO connectors for building SLI configurations in the standard location near the video outputs.
The reference card’s 6- and 8-pin power connectors are replaced here with two 8-pin ones to ensure that the card has enough power at increased frequencies. The PSU requirements haven’t changed, though. The N680GTX Lightning is recommended to be used with a 550-watt PSU, just like the reference card.
Although massive, the exclusive Twin Frozr IV cooler is only secured with four screws around the GPU. It is quite easy to take off. We only have to remove the heat-spreader that covers most of the PCB to have a good view of the graphics card.
The PCB is in many ways similar to the one of the R7970 Lightning model, the only obvious difference being the GPU chip.
A number of discrepancies can be found on closer inspection, though.
The unique 12-phase power system incorporates gold-plated solid state chokes, CopperMOS transistors, Dark Solid capacitors and tantalum-core Hi-c capacitors.
Each power phase has a dedicated indicator based on blue LEDs. It can be seen on the reverse side of the PCB. The gold-plated chokes are especially impressive:
Besides the marketing effect, the Golden SSCs ensure stable voltages and overcurrent protection at high loads. The N680GTX Lightning also features a special Lightning Power Layer PCB that helps reduce interference and increase stability at overclocking. All of this is referred to as Unlocked Digital Power.
The GPU Reactor module on the reverse side of the PCB is expected to ensure even more stability in overclocked mode (up to 200% more).
The GPU voltage regulator is managed by an 8-phase PWM controller CHiL CHL8318.
Like every other Lightning series card from MSI, the N680GTX is overclocker-friendly with such features as dual BIOS (with LN2 settings, no voltage limitations and a higher power consumption limit) and three connectors for reading voltages (V-PLL, V-MEM and V-GPU):
So, this graphics card looks perfect for extreme overclocking with liquid nitrogen or something like that.
The GK104 GPU was manufactured in Taiwan on the 18th week of 2012. It is revision A2:
Its base clock rate is lifted from 1006 to 1111 MHz (+10.4%) by default and can be boosted to 1176 MHz. Otherwise, it is a regular Kepler with standard specs (you can see them in the table above). Its voltage is 1.175 volts in 3D mode and 0.988 volts in 2D mode.
Our GPU turned out to have a high ASIC quality of 96%:
The card carries 2 gigabytes of memory in eight GDDR5 chips manufactured by Hynix Semiconductor. They are labeled H5GQ2H24MFR R0C:
The memory frequency is left at its default 6008 MHz, so the rest of the memory subsystem parameters are identical to those of the reference card’s.
Here is a summary of the N680GTX Lightning specs: