Alas! NVIDIA was just playing the waiting game, releasing the last of 680i chipsets from their warehouses for the gamer who values memory quantity over speed. Now, the performance chipset from NVIDIA has finally arrived. The C73XE/MCP55P forms the 790i platform that supports everything speedy. DDR3, 3 Way SLI, and the usual connectivity.

With Asus engineers working their magic, we're expecting a lot more from the Striker II Extreme than just any run-of-the-mill 790i motherboard. Nothing less than full-blown MCH abilities, cool SPP features, and not to forget, overclocking to embarrass Intel chipset motherboards. Will it outperform it's predecessor's track record? We hope!

Packaging for the Asus was top-notch, with extensive use of compartmentalisation to keep things neat, tidy, and in-place. It's hard to fault Asus when you think about the amount of accessories thrown into the RoG line of motherboards. There is even a separate box to keep the accessories in place!

Brimming with items, popping the lid of the box brings you to individual "Ziploc" bags of items. You'd find common accessories in there, but Asus put in effort to make the deal a lot more tantalising. Amongst them: a low-noise blower is supplied to fit over the heatsink fins for the motherboard VRM, rubber feet for open-concept debugging/benchmarking, external standalone diagnostic LCD, conversion barbs and tubes for the Fusion MCH waterblock, temperature probes, lighted I/O bracket, nylon cable ties, manuals, drivers and a free copy of Company of Heroes.

Asus's brute-force approach to accessories will not be welcome by all, especially the lean-and-mean users and environmentally-conscious. It does have a few quirks. For one, two axial blowers should have been supplied to cool both portions of the heatpipe assembly, whilst the finicky diagnostic LCD could at least be weighty enough to stay on a suface (table etc.) without being thrown into the air by the sheer elasticity of the captive cable. I too wonder if it adds significantly to Asus's costs to supply black nylon cable ties - something that would at the very least, complement their PCB color scheme.

Power management is causing a big hoo-ha over in Taiwan at the moment, since Gigabyte kicked off a green movement that had Asus and Foxconn scurrying to compete. Here, the focus is on the power consumption of the CPU, with the pricipal idea being a dynamic approach to Vcore regulation. These attempts can range from loadline calibration to phase deployment techniques. Indeed, much lies after the EPS power connector seen on this Striker II Extreme. Sources tell us that the EPU chipset is in fact a power management buck converter from Analog Devices.

8 phases of DC-DC conversion promises power and stability to the CPU run on the Striker II Extreme. Where electrolytic capacitors are needed, only solid-polymer capacitors are found. SMD ceramic capacitors continue to be the mainstay where close-to-component power bypass is necessary. It's heartening to see the CPU socket indent completely filled with ceramic capacitors - an attempt at keeping power noise at bay. Multiphase DC-DC buck conversion continues to the rest of the motherboard there critcal Vcc sources are needed.

Thermal Management

For all the engineering that goes into the power regulation of the motherboard, nothing is acheived without proper thermal design to keep heat in check. Belonging to the RoG line, the Striker II Extereme is the purported overclocking kingpin (no pun intended) amongst 790i Ultra SLI motherboards. This means proper cooling where it counts, especially when you consider that the MCP73XE runs at a 1.55V default Vmch on the Striker II Extreme. The heatpipe cooling proves reliable on the Striker II Extreme thanks to the employment of a quality OEM in Taiwan. Nontheless, overclockers should keep some air moving over the fins of the heatpipe assembly if any significant stable grounds are to be gained without trading off component lifespan.

Notable is the the extensive use of ground and power planes on the PCB to distribute heat, a design technique which Asus calls the Stack Cool 2. Solder forms the contact filler between the copper base and heatpipes, a detail often overlooked by cooler-makers. The unfortunate part was that we found a piece of thermal pad as Thermal Interface Material on the Striker II Extreme. More contact would have been possible if heatsink compound was used instead.

Chips & More Chips

Semiconductors make the world go round these days, so let's focus on the leggy creatures on the Striker II Extreme.

C73XE, aka nFORCE 790i Ultra SLI.

Southbridge duties: MCP55P.

JMicron JMB363: eats up PCIe x1 and spits out 2xSATAII + 1xPATA ports.

Marvell GbE.

Miscellaneous uContoller, presumably for driving the diagnostic LCD.

Winbond GPIO (SuperIO).

Winbond supplies the BIOS ROM.

W38791G: Winbond's Hardware Monitoring solution.

Over the years, configuring PC hardware has shifted from inherent jumper settings to software controls in the BIOS. Today, we even have on-the-fly frequency and memory adjustment within the OS. For enthusiasts, the BIOS layout plays a role in the user friendliness of the motherboard. The Striker II Extreme engineers have kept this in mind, and our 0504 BIOS revision is overwhelming with options.

RoG greetings!

Overclocking options on the first page. very handy!

Memory timings.

CPU Configuration.

Spread Spectrum controls.

Basic options.

Save that Fluke! LAN cable checker onboard.

Device Configuration page.

RAID page.

"Advanced" controls for simple functions.

Temperature monitoring page. No monitoring of individual cores, however.

Comprehensive fan controllers.

BIOS settings can be saved, well suited to testing out settings side-by-side and optimising presets for different memory pairs.

Preset-overclocks are available for those lazy to overclock their CPU. Yes, it can clock your chip to QX9770 speeds.

Up to 200MHz PCIe bus. Perfect for the extreme benchmarker on a SLIing Spree.

Rather kinky, I found, was the logo watermark that immediately brainwashes users into RoGs when they use the BIOS.

In the past few years, yours truly has observed that the overclocking community has become more knowledgeable about the impact of voltage settings on signalling and switching of semiconductor devices. Motherboard manufacturers are catching up upon this wave of knowledgeable enthusiast-users, and dropped conservative and limited options in the BIOS for comprehensive and extended ones. The race was pretty much started by DFI, and subsequently Gigabyte's first DQ6 motherboard. Today, outlandish options (I've yet to know of any subzero-cooling users venturing into 2.00V Vcore for benchmarking) lace highend offerings from mainboard makers, something overclockers embrace with glee.

The individual GTLref adjustment on the Striker II Extreme is a rather new feature, which I believe was first implemented on the tweaked-out and oversexed (if a little rare) Foxconn BlackOps. With so many options to explore, overclockers are spoilt for choice. Systematic patience would be the key to "maxxing" out the motherboard. We can only hope that phantom options don't pop up to spoil the show for Asus.

In the previous pages, we've mentioned that the Striker II Extreme has a well-furnished BIOS with overclocking appeal. Asus however, had let us down in their previous flagship (the Maximus Extreme) which sported some non-responsive "phantoms" within the BIOS pages. While the rest of the hardware sites were busy throwing out exclusive reviews of 790i motherboards, the VR-Zone Team had been busy tweaking our overclocks. We don't believe in giving half-assed 400x11MHz Yorkfield CPU-Z shots - it's as obscene as a baboon's backside to the discerning reader.

With so many options on hand, where do we start? Auto of course! With Vdimm bumped up to 2.22V, Vpll at 1.66V, and Vfsb at 1.48V, FSB was gradually pumped up.

With ease, we reached a stable 453MHz on FSB. This is whoppin' cool considering that the same CPU hit a FSB "wall" of just 441MHz on the X38 Maximus Extreme. Think about it, no messing with blazing soldering irons or freezing Nitrogen! The VRM took on our 1.625V CPU Vcore without much complaint to allow a 4.3GHz Yorkfield to run the Show.

"The Show?" you ask. That's the show!

Of course, more work was in place for this promising motherboard. How could we let the array of options go to waste?

To the common eye, traces on a motherboard run amok, twisting their way through fibreglass and copper traces. Some decidely snake around after running about in circles, others follow a straight path with an occasional turn to facilitate the data highway.

In truth, motherboard design is far more complicated than it seems - designers could throw the circuit at a PCB layout program, and force it to lay the traces automatically. Chances are, the board would not work as intended. Motherboard design is an Art, which probably explains why this Fengshui Motherboard will never make it past POST (if one was ever made).

When copper traces are laid side by side, various things can occur at once. Magnetic and capacitative coupling immediately come to mind. What about the number of layers of PCB? Lengthy traces and resistive routes? At high frequencies that components run today, ringing is taken care of through impedance matching while noise is attenuated via differential signalling and grounding techniques. Signalling at high frequencies remain an engineering challenge, and the most successful to date, has to be the Gunning Transceiver Logic (GTL) invented by then Xerox researcher - William Gunning.

Signalling - GTL

GTL signalling on current generation Intel platform are no longer the original, which was specified for operation between tens to hundreds of MHz - insufficient by today's standards. Simply said, the GTL signalling system sets a "window" for logic circuits to determine if the tranceivers are reading a logic high, or logic low. By virtue of the innocent inputs/outputs of chipsets, overshoots and undershoots of these signals are often misread. These misreads are what we know as errors, that is, corrupt data.

When overclocking, the frequencies of signals within the system are raised. These signals, with their increasing state-of-change, interacts with the 3 basic electrical characteristics of resistance, capacitance and inductance. This, is what we know of as reactance. Due to imperfections (design tolerance, thermal degradation of components during wave soldering, trace layout, grounding planes, impurities of the PCB substrate, inconsistent PCB thickness, flux, termination voltage fluctuations etc.), ringing signals can arise from overclocking. Ringing, as they will tell you in engineering school - is not good at all for signal integrity.

As an overclocker, competitive or otherwise, moral integrity is paramount - no cheating, no timer tricks, no pixel-nulling. The next important integrity, would be that of the signals that tick your clocks. Earlier on, we had mentioned that reactance on inputs/outputs, with increased frequencies causes ringing, which overshoots and undershoots on the transceiving pin of the chipsets. The "window" of the I/Os get confused and writes in the wrong logic highs and lows. GTLref is a termination voltage (a termination voltage sets the reference point to which a chipset I/O recognises the incoming signal as a logic high or logic low) engaged by Intel in existing systems which sets the "window" for signalling.

Voltage settings used to achieve results on the next page.

Through manual adjustments of the GTLref, users can control the inadvertent ringing resulting from overclocking. On the Striker II Extreme, you'd see the real-world use of GTLref control for overclocking. Not one, but all four GTLref voltages can be individually adjusted on the CPU. Knowing that each core on the die responds uniquely to voltages and cooling, individual GTLref adjustment is the key to acheiving high FSB frequencies. Our last record on the QX9650 was 456MHz on the FSB, let's see what those new options will do for it!

With manual adjustments, we moved from 453MHz on the FSB to 468MHz, bulldozing down the 456MHz effective FSB "wall" of the Core 2 Extreme we had on hand. All these were done with memory running at CL6, well over 1.7GHz effective data rate.

To accomodate cooling limitations, we dropped the FSB a little to acheive a stable CPU clock.

3DMark's multithreaded CPU benchmark benefitted from the clock increase. All the above results were run on Vista x86 without SMBus drivers installed. As much as the VRM kept our CPU stable, we could not help but notice the loud whining of the inductors under high current stress.

CPU VRM Explored

To successfully power the millons of transistors within a CPU takes a healthy dose of engineering. Remember a time when linear regulators powered first generation desktop CPUs? Today, nothing less than PWM power controllers are ther norm. CPU power has always been of concern to overclockers due to the need for excess voltage when running above-spec, and the eventual debate of quality and quantity drops into view.

Two main parameters exist when evaluating mainboards for CPU Voltage Regulation Module (VRM), namely Vdroop and Vdrop. The supply that runs the bulk of the CPU is termed the Vcore. Due to the large number of transistors sinking current during load, current draw increases and resistive losses (in the inductors, power plane, and contacts) causes Vcore to fluctuate. This is not expected of a quality VRM.

Like many overclockers, we are particularly keen to find out if the Striker II Extreme can take the load of a full blown overclock. With the CPU on 400x10MHz, we proceeded to raise Vcore to a conservative 1.575V in the BIOS. Loadline Calibration was enabled.

Clearly, Vdrop error has been kept low, with our budget meter registering a rather promising idle Vcore of 1.574V. Proceeding to load the CPU with 3DMark06 (multithreaded benchmarks/applications put the most stress on the VRM), we checked the Vcore again.

Instead of a positive Vdroop, Asus and Analog Device engineers have cleverly worked a small boost into the Vcore to compensate for the possible losses. It remains a question if a negative Vdroop is over-compensation, since 12mV still falls within the margin of error is allowed in powering Intel's Core 2 Extreme processors.

Excerpts of Intel's datasheet for their QX9xxx series of processors.

Asus's EZ Flash

As kinky as it sounds, Asus's EZ Flash is not a prebuilt pornography plugin for their motherboards. It offers an effective environment for rapid and fuss-free BIOS updates. Below you'd see us flashing the Striker II Extreme with nothing more than a flashed-based USB drive.

With Asus's track record at delivering motherboards with incompetent BIOS revisions, EZ Flash is no doubt a Godsend if you asked me.

Going Green

EPU is the brainchild of a collaboration between VRM solutions company and Analog Devices and Asus, an attempt at reducing power consumption on their motherboards. Along with the ineveitable switch to leadfree solder, many companies, such as Asus's long time rival Gigabyte, have been promoting their motherboards as "green" products.