Diving Deeper into the Lightning XE
Diving Deeper into the Lightning XE
MSIís Power4 Architecture has made a comeback on the Lightning XE. This brings an enhanced PWM layout, independent memory power inputs, a copper MOS design and Proadlizer solid state super capacitors onto this particular GTX 580.
The starting point of any high end GPU design lies with the strength of its PWM layout and MSI has truly gone all out for the Lightning. They have instituted a 12-phase GPU PWM along with three phases for the GDDR5 memory and a final dedicated phase for the PLL/VDDCI PWM. In total, that brings the Lightning to an impressive 16 phases for the PWM. As can be seen, the PCB has actually been widened by a good ĺĒ to ensure this massive PWM has enough space.
In terms of memory, MSI has retained the reference versionís twelve chip layout (or two ICs per 64-bit memory controller) but instead of using 128MB modules with a 32x32 array design, they are using 256MB ICs with a denser 64x32 internal layout. This move allows the same number of modules to be used but tends to increase the overall latency due to the more complex structure.
Lightningís underside is a sight to behold with an extended and lengthened PCB which has a quartet of Proadlizer solid state capacitors sitting at its core; one of which is dedicated to the memory while the others are for the core. These are supposed to provide additional capacitance and lower electrical resistance for stable power.
Along the PCBís edge are three DIP switches with a fourth being located near the PCI-E slot connector. The main grouping of three includes an OPC Unlocker that allows the core to ignore any power limiter that has been placed upon it, a V-Switch for quick voltage tuning and a PWM Clock Tuner which essentially overclocks the PWM clock to 310Mhz from the reference 260Mhz. The fourth switch is dubbed XtremeCool for working around the GTX 580ís ďcold bugĒ and should be used when overclocking with LN2.
Next to the three main DIP switches is a toggle used for quick BIOS switching. The Lightning holds two BIOSes onboard; one of which houses the standard overclocked file and another which is tailor-made for high end cooling solutions since it implements aggressive voltage presets. When used in conjunction with the XtremeCool toggle, this should allow extreme overclockers to push speeds to the heartís contents.
One other interesting thing that the Lightning brings to the GPU overclocking world is a dedicated memory power input path. In laymanís terms, this is achieved through power distribution via one of the 8-pin PCI-E connectors in tandem of a 3-phase PWM instead of drawing the GDDR5ís current through the PCI-E slot connector on to a single phase PWM. Naturally, there are benefits like lower ripple and slightly more current stability but the vast majority of users likely wonít notice a difference other than increase component life.
In order to provide higher current to the GPU core, copper-based MOSFETs were used. Naturally, a cooler component can cope with higher loads so MSI implemented two copper layers (one above and one below the die) which allow quick dispersion of heat from the FETís die package. The result is actually quite impressive: a 20% temperature reduction and a doubling of current capacity from 20A to 40A.
Much like some other manufacturerís MSI has instituted a PCB design which effectively eliminates electrical noise. Called the Lightning Power Layer, it isolates the circuits for various card components in order to increase stability and enhance cooling through the use of copper.
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