Almost all of the RTX 4090 cards feature increased maximum TGP, which is “Total Graphics Power,” for overclocking. There are models with TGPs as low as 500W (ZOTAC); however, most GPUs go far higher. There are models with a maximum power of 600W like NVIDIA Founders Edition, ASUS ROG Strix or Gigabyte Gaming. But, until the announcement of Neptune, none of the cards had previously gone higher.
From the Colorful iGame line, the iGame Neptune is a liquid-cooled RTX 4090. Although it shares a PCB with the iGame Vulcan series, its clock speed is somewhat greater (2640 MHz vs 2625 MHz). The maximum TGP of 630W is also greater (80W higher than Vulcan).
This TGP is the highest TGP currently supported by any RTX 4090 GPU. This is why Colorful advises using a 1000W power source.
Custom RTX 4090s were projected to surpass the 600W TGP limit at some time, but such settings were to be expected from enthusiast OC cards, such as the forthcoming Galax HOF.
The Neptune has been sent out for reviews; however, it appears that few have been published as of yet. The Expreview team did publish a review, and they validated that the unit comes with a default 550W TGP and a 630W maximum. The performance was unaffected by unlocking an additional 80W power because the 100W higher default TGP was already so high. In 3DMark Time Spy Extreme, the card’s performance gain was only 0.7%.
Moreover, despite the card’s default TGP of 550W, the max value measured using the NVIDIA PCAT power monitoring program was just 470W. A complex water cooling system also contributed to its unusually high 47W idle power consumption.
For graphics cards with non-standard 450W+ TGP, enthusiasts should pay special attention to the 12VHPWR connection. A review by TechPowerUP found no difference between the 450W and 600W versions of this connection when used with 450W RTX 4090 GPUs. A 600W cable is strongly suggested for any card that exceeds the default TGP, particularly manually and factory-overclocked GPUs.
In addition, the 600W requirement may be fulfilled by connecting four 8-pin power cables to 12VHPWR converters. When just three 8-pin cables are used, this smart NVIDIA adapter will return to 450W standard. Igor’sLAB thoroughly discussed this. It’s important to remember this while selecting a card, like the iGame Neptune.