Asus P5N-E SLI Nvidia nForce 650i SLI

BIOS and Overclocking

Despite being on the market for only a scant month or so, the P5N-E SLI has gained a reputation as a great budget overclocking board, thanks to a few choice reviews around the web. While Asus doesn't push the overclockabilty of this board as a prime feature, in our testing, we've found that the board is quite tweakable, if you're willing take the time to endure a little hassle.

The shipping BIOS for this motherboard, 0202, is somewhat limiting in its feature set. Asus recently released a newer 0307 BIOS to the world which seems to fare a bit better, but most overclockers are still reporting issues with this board. Our testing was done with an 0304 BIOS, which we found to provide excellent overclockability and solid stability. Asus uses a Phoenix BIOS for this motherboard, with all of the overclocking utilities featured under the "Advanced" menu. 

Voltage Levels

FSB/Memory Levels

Like the high-end nForce 680i, the nForce 650i makes for an excellent overclocker as front side bus speeds can be tuned independently of the memory bus. This allows you to keep your memory speed at a reasonable level while cranking your FSB (and peak overclocks) as high as they can go, without the memory being a potential stability issue. The board supports front side bus speeds up to a whopping 3000 MHz, giving quite a lot of headroom for Intel Core 2 processors which have a 1066 MHz FSB by default.

Memory Timings

Fan Speed Controls

We didn't get quite that high in our testing - the maximum front side bus speed we were able to attain was 1933 MHz, however, we were only able to have a stable system to run through our full benchmark suite at 1866 MHz. 1866 MHz is still a very high front side bus overclock, and even more impressive is that we were able to attain these speeds with stock voltage and passive chipset cooling. Cranking up the Northbridge voltage levels did not improve our overclockability, and neither did putting active cooling on the Northbridge heatsink.

The peak (stable) overclock which provides us with the best performance was running our Core 2 Duo E6600 (2.4 GHz) processor at 1666 MHz FSB on an 8x multiplier, which gave us a clock speed of 3.33 GHz. This is the level we ran our processor at for our "overclocked" series of benchmarks on the following pages.

One oddball aspect about this board is voltage tweaking. Instead of being solid voltage amounts to push to (for example, 1.9V, 2.0V, 2.1V), the P5N-E uses non-standard voltage levels (1.92V, 2.012V, 2.085V) for processor, memory, and Northbridge voltage modification. Being a percentage or two off in terms of voltage likely won't hurt any components, but it didn't install confidence either.

The board support Asus Q-Fan for low-noise computing, although one can only control two 3-pin fans through the BIOS. We should note that the board only has a scant three 3-pin connectors, so if you're looking to hook up a lot of fans, you might want to look into a drive-bay mounted fan speed controler.