ASUS P5N32-E SLI Plus: BIOS & Overclocking
The P5N32-E SLI Plus uses an Award BIOS that is very comprehensive and packed with features. Like many other Award BIOS menus, this one is easy to navigate and well laid out. From within the BIOS, users have the ability to configure, enable or disable all of the board's various integrated peripherals, and can monitor fan speeds, voltages and clock speeds.
The P5N32-E SLI Plus' BIOS is highly configurable and offers many of the same options featured on the Striker Extreme. There are seven main tabs and inside of almost every tab are several sub-menus.
Besides the usual set of rather standard BIOS settings, a couple more interesting options are also included such as the ASUS music alarm, fan speed control menu, OC profiles, EZ Flash 2 and the extensive PC health monitor. The ASUS music alarm allows you to set a alarm that plays music from an inserted audio CD. The time and days of the week that the alarm should be active on can both be set from the BIOS. The fan speed control menu allows you to individually control all 8 fan connectors. The OC profile features allows you save and load your overclocking settings. The EZ flash 2 utility allows you to flash the BIOS without requiring a bootable floppy disk. Finally, the PC health monitor lets you see real-time data like voltages, temperatures and fan speeds.
While these options are quiet useful, the real fun is in the 'Extreme Tweaker' menu. Inside, you'll find just about every voltage, frequency, multiplier, ratio and timing setting you'll need to push your CPU beyond its manufacturer recommended limits. Before you can get to all the manual controls, you first need to select the AI Tuning mode you would like to work in. There are five modes to choose from, they are Manual, Auto, Standard, AI Overclock, and AI N.O.S. Manual mode allows you to individually tweak the various BIOS options as you please. Auto mode loads the optimal default settings while Standard loads the standard settings. AI Overclocking mode loads overclocking profiles with optimal parameters for stability when overclocking. Finally, AI N.O.S. mode intelligently determines the system load and boosts performance while the system is performing particularly demanding tasks.
The P5N32-E SLI Plus allows the user to manipulate the CPU multiplier, although you are limited to decreasing the multiplier unless you have an unlocked processor. The front side bus frequency can be adjusted in 1 MHz increments, from the stock frequency to as high as 3000MHz. PCI-E express frequency can be adjusted for each of the three PCI-E x16 slots individually, from 100MHz to 200MHz. The multiplier to the LDT bus between the north and south bridge can also be adjusted anywhere from 1X to 8X. There are a lot of memory timing options available and ASUS has divided them into two groups, one for the major settings and a second group for the more advanced options.
The memory clock mode can be switched between linked and unlinked. In linked mode, the memory clock depends on the FSB. The two frequencies are separated by a ratio that can be 1:1, 5:4, 3:2 or 'sync' mode. In sync mode, the ratio being used it determined by the chipset in real-time. In unlinked mode, the memory clock and FSB are independent of each other. This can be an asset in certain situations where the provided memory ratios in linked mode just don't fit the bill. Choosing unlinked mode will unlock the memory bus frequency setting, which can be set to anything from 400MHz to 2.6GHz.
The BIOS offers thorough voltage adjustments. The Vcore voltage can be adjusted as high as 1.9V, in 0.00625V intervals. Memory voltages can be set as high as 3.425V, in 0.025V intervals. The HyperTransport voltage can be increased to 1.95V in 0.05V intervals. The north bridge can be fed up to 2.75V, also in 0.05V intervals, while the south bridge goes as high as 1.85V. The VTT bus of the processor can be increased in 0.05V intervals up to a maximum of 1.55V. The DDR2 memory controller's voltage can also be increased by as much as 30mv separation in either direction.
Overall, we found the P5N32-E SLI Plus' BIOS to be excellent. There is an abundant selection of overclocking options and the voltage adjustments are very generous. The menus are well laid out and it only took a couple moments to figure out where everything was.
We took a Core 2 E6400 processor and set out to see if the P5N32-E SLI Plus' extensive BIOS settings could amount to equally impressive overclocking results. We loaded the BIOS' optimized defaults, then increased the FSB as far as we could go without having to increase voltages to achieve stability. The frequency of our Corsair TWIN2X1024-8500 modules were locked to their rated speed of 1066MHz in the BIOS' memory multiplier settings.
We were able to take our E6400 CPU to 3.04 GHz, by raising the FSB to 380MHz. This is the highest speed our system was able to handle with perfect stability. We know from past experience that the particular E6400 we used was capable of a bit more than this and our RAM was locked at their rated speed, so it was probably the board that was preventing us from pushing further at stock voltages. We were able to boot into Windows at slightly higher frequencies but we weren't able to stay there very long since our system was terribly unstable. Out of curiosity, we lowered the multiplier from its default of 8 to 6, the lowest setting we were allowed to go, and tried to achieve a higher FSB overclock. Reducing the multiplier, along with our past experience with the particular processor we were using safely rules out the possibility that our CPU was holding us back. Unfortunately, we were unable get anything more out of this setup at stock voltages, even with a reduced CPU multiplier. Overall, the P5N32-E SLI Plus is a decent overclocker. The FSB overclock it was able to achieve is about average compared to other enthusiast boards.