The Rampage seemed to be familiar to us from our Maximus review so we dived into the testing with stacks of optimism but that rapidly faded. The first question mark was raised as we had been sent BIOS 0207 by Asus however the board had BIOS 0219 installed. There was no way we were going to install an earlier BIOS as that's a step backwards in anyone's book. As the X48 is all about the latest processors and bus speeds the first processor up for testing was a Core 2 Extreme QX9650 on a 1,333MHz front side bus. The Bios burst into life but Windows refused to load. Switching to a 1,600MHz QX9770 got everything going successfully. Once we had 64-bit Windows Vista installed we were able to investigate the mysterious ways of Penryn and why the heck we couldn't get the QX9650 to run on default settings.
It seems that the answer lies in the depths of the voltage settings which is a bit awkward because Asus offers you a total of seven settings to play with. The first step is to use the hardware monitor in the BIOS to work out what settings are running by default and use that as a starting point.
You can crank up the CPU PLL, North Bridge, DRAM, FSB Termination, South Bridge and SB 1.5V Voltages without too much trouble provided you use the system of colours in the BIOS to avoid trouble. Green is safe, yellow is pushing your luck and red is decidedly risky. The odd one out in the settings was the CPU Voltage as our Penryns were very fussy about the amount of power they wanted.
In the past we have been able to run our QX9650 on a variety of motherboards including a Gigabyte X48-DQ6 on Auto settings or with extra voltage for overclocking. On the Rampage we had to manually set the voltages to get the system running and were then able to raise the core voltage to 1.40V for overclocking.
The QX9770 was easier to get running as the Auto BIOS settings worked perfectly but when it came to overclocking the QX9770 didn't want anything more than 1.24V core voltage. That's the standard voltage applied through a manual setting and when we raised the voltage the processor refused to overclock.
Also, it was also clear that Rampage is overvolting the memory by about 0.1V more than the setting chosen, which is a bit naughty. Our conclusion is that the BIOS is a work in progress that is nearly - but not quite - finished.
Although it took a fair amount of work to get our QX9650 and QX9770 systems running satisfactorily, once we got there the results were very impressive. The systems were powerful, cool, quiet and stable but it's hard to give a big thumbs up when you can't boot in to Windows on Auto settings.
The Rampage Formula takes over from Maximus with all the bells and whistles we've come to expect from Asus' top-end boards. However the move from Intel's X38 to its X48 chipset doesn't make a huge difference to real world performance and it is clear the BIOS still needs some work before it even has some basic functionality. We'd recommend you wait a few weeks and keep an eye on the BIOS updates before you plump for this one.