Overclocking Experiments

Mainboards on Nvidia nForce 790i SLI chipset will definitely be of interest to some computer enthusiasts. If you want to combine a contemporary quad-core processor, DDR3 memory and high-performance graphics subsystem with a couple of GeForce GPUs, this is the only way you can. However, Nvidia believes that mainboards on their latest LGA775 chipset may also be of interest to enthusiasts with less extreme demands. nForce 790i SLI developers stress its phenomenal overclocking potential, which we absolutely had to check out starting with finding maximum FSB frequency when ASUS Striker II NSE remained stable.

We put together a special testbed on ASUS Striker II NSE, which also included 2GB of Corsair DDR3-1800 TWIN3X2048-1800C7DF G, Gainward Bliss 8800GTS 512MB graphics card, Western Digital Raptor WD1500AHFD HDD and SilverStone SST-ST85ZF PSU. The participating processors were cooled with Zalman CNPS9700 LED cooler.

Contemporary mainboards do not have any problems with dual-core Core 2 Duo processors overclocking any more. Nevertheless, we decided to start our practical overclocking experiments on ASUS Striker II NSE with Core 2 Duo E8500 overclocking. We lowered its multiplier to 8x and managed to overclock the processor to 4.24GHz. It is a pretty good result considering the FSB frequency was set at 530MHz.

The system remained stable and reliable in these conditions, which was tested with a 1-hour run of Prime95 25.6 test in Blend mode. The memory was also working problem-free at 1816MHz with 7-7-7-18-1T timings.

However, we had to increase North Bridge voltage to 1.54V and raise the following processor voltages: CPU Voltage – to 1.4V, CPU VTT Voltage – to 1.3V, and CPU PLL Voltage – to 1.64V. Vmem was set at standard 2.0V.

Although we are talking about easy and problem-free overclocking experience, there still are some problems an overclocker may face, most likely because of some BIOS issues. For example, during our test session the mainboard sometimes refused to boot reporting over-overclocking. As we found out it was occasionally setting the processor multiplier incorrectly and that’s what caused the problem. Luckily, in this case BIOS doesn’t reset the parameters during next boot-up but suggests entering the BIOS Setup to make some adjustments. So, I guess we can live with that.

Especially since in some situations ASUS Striker II NSE does indeed offer unprecedented flexibility during overclocking. To check out the real value of these options we installed a quad-core Core 2 Extreme QX9650 processor, which we could normally overclock about to 460MHz FSB on Intel based mainboards.

Once we lowered the multiplier to 8x, we could get Core 2 Extreme QX9650 to run on ASUS Striker II NSE at 475MHz FSB. The CPU overclocked to 3.8GHz.

We ensured stability by raising processor Vcore 1.4V. As for the memory, it worked fine at 1782MHz with 7-7-7-18-1T timings and 2.0V nominal voltage.

Unfortunately, further FSB increase resulted in stability loss and no voltages or CPU GTL_REF parameter could help regain it.

However, we should be pleased with the obtained result, as far not every mainboard for enthusiasts can overclock quad-core processors that well. The only thing that can spoil the glorious achievement is the fact that to ensure stability we significantly increased the chipset voltage - to 1.7V, CPU VTT Voltage – to 1.5V and CPU PLL Voltage – to 1.8V. Moreover, we had to manually set CPU GTL_REF0 and CPU GTL_REF1 at -51uV and -56uV respectively. In other words, we had to put some effort in conquering 475MHz FSB.

On the other hand, we actually need to push the voltages so aggressively during quad-core processor overclocking only in the very end. For example, at 455MHz FSB our Core 2 Extreme QX9650 system was absolutely stable at much more acceptable settings: 1.4V chipset voltage, 1.4V CPU VTT Voltage and 1.6V CPU PLL Voltage.

So, we can certainly recommend ASUS Striker II NSE as a great choice for overclocking experiments.