Obviously the one aspect that really sets the MSI
NX8600GT Twin Turbo videocard apart from the competition is the "Twin Turbo"
button on the back. Enabling or disabling the button has an affect
on the videocard's core and shader clock speeds; shifting GPU speed from 600MHz to 620MHz, and shader frequency from 1458MHz to 1512MHz. The videocard memory remains at 1600MHz clock speed regardless of Twin Turbo being engaged or not. A unique feature, yet slightly cumbersome as MSI's Twin Turbo only kicks in after rebooting the computer.
The reason shader overclocking is not immediately enabled by Twin Tubro has to do with how it's implemented here. The MSI NX8600GT Twin Turbo has two BIOS', one operating the nVidia G84 core at
600 MHz and Shader at 1458 MHz. The other BIOS, the one enabled with Twin Turbo, sets the clock speed to 620MHz / 1512 MHz core/shader respectively. To switch between the two, one simply presses the "TT" button on the back of the MSI NX8600GT Twin Turbo videocard in or out.
The Twin Turbo button on the MSI NX8600GT Twin Turbo videocard toggles between two
BIOS settings, one with overclocked shader and GPU clock
With the Twin Turbo feature turned off, the MSI NX8600GT Twin Turbo videocard is already pretty heavily pre-overclocked from the factory. A standard GeForce 8600GT videocard operates with a GPU speed of 540 MHz, memory speed of 1400MHz and shader clock speed of 1188 MHz.
To use the Twin Turbo feature, you'll need to restart your PC after
selecting a mode. That forces the videocard to use the alternate BIOS with
the Twin Turbo settings. If you press the "TT" button while the computer is
on, the world ends. Okay no, nothing bad happens; Windows doesn't
crash and the videocard is not harmed. Yet the crux of the
situation is that you still need to restart your PC to use TT.... so if
you're in the middle of a game and need "just a little more speed" you'll
unfortunately have to stop, reboot the computer and let the new
BIOS initialize the new clock speed settings.
button shown disengaged. When engaged, it lights up red. Next
to this in the PCI bracket shield is an SPDIF audio cable pass-through cable
hole. That allows the Geforce 8600GT to be connected to an I/O situated
SPDIF audio jack so audio can be integrated into the Mazarine
DVI monitor jack below.
When the TT button is engaged the letters glow red, indicating the status (on/off) of the feature. If you decide half way through a game to turn the Twin Turbo feature off, you'll need to power down and restart the entire computer. Bah.
So there you have it. The MSI Twin Turbo feature
is certainly unique, and that's what PCSTATS likes to see coming from
graphics cards companies. Twin Turbo's implementation isn't as
user friendly as it could be, and the shader clock speed isn't overclocked
independently from the core or memory either. Still, we here at PCSTATS really
like the concept.... and it will be pretty cool if MSI devises software to
work in conjunction with the TT switch for future implementations so the change is
instantaneous. What do you think? The need to reboot the computer between settings is too inconvenient, so just leave the Twin Turbo feature enabled right from the get go! Overclocking is up next, ready for some speed?