Asus P5N32-SLI Deluxe nForce4 SLI X16 Intel Edition

Leave it to Asus to try something different with the bios of the P5N32-SLI Deluxe.  The AMI BIOS we found in control of things had a few screens with typical offerings that one would expect, but also a slew of settings that allow for some fine tuning.  Initially, we were able to view the type and speed of the processor as well as the total usable amount of RAM installed.  To keep track of which drives were installed, and where, we could take a look at the IDE and SATA devices on the first menu screen.  While some newer boards are cutting back on IDE options, here we can see that a Secondary IDE channel is alive and kicking.  Of course, with so many options available to users including multiple SATA RAID options, one also has to decide the boot sequence.  In our case, the choice is made much more simple by assigning the single hard drive as the first boot option and the CD-ROM as the second. 

Examining the BIOS of the Asus P5N32-SLI Deluxe And now time for something completely different...

Unfortunately, getting the system booted was not always that easy.  In many cases, booting up the P5N32-SLI resulted in a blank monitor screen and we had to manually shut down the board using the kill-switch on the power supply.  Originally, we thought this might have been a heat-related issue, as the system typically would not reboot after running benchmarks and the like.  After checking fans and airflow, we were convinced that the setup, at least, was not at fault.  We also noticed that the next boot after using the PSU kill-switch, would invariably halt during POST with the message that "overclocking failed or overvoltage failed".  The problem with this is that in just about every case, we were neither overclocking nor overvolting any of the components.  Investigating the issue, we found that in the Hardware Monitoring section of the BIOS, that the CPU was consistently undervolted, usually by a solid volt off of the expected value.  That is, even if we raised the voltage elsewhere, the VCORE Voltage would be one volt lower.  We managed to gain a bit of stability by manually raising the CPU voltage, but still found that the system became unresponsive from time to time.

We also had what appeared to us to be a small discrepancy when installing a second 7800GT card for SLI testing.  During POST, the PCI-E configuration was shown as 16-1-1-1-1, which was identical to the readout when only one card was installed.  In our experience with other nForce4-SLI boards, a one-card setup might show 16-1-1-1-1, but installing a second card would show the division of the PCI-E graphic card lanes, giving us 8-8-1-1-1.  We were able to test the board using SLI, but the results are debatable without knowing if the full 32 lanes were opened up on this board.  After speaking with Asus concerning these matters, we were sent a few new BIOS versions, including a second board to try, but all issues persisted throughout.  If stability is a top priority for you (and for who is it not?), then you might want to wait until Asus irons out some of the P5N32-SLI's BIOS wrinkles.

Overclocking Tools There's always room for improvement

Overclocking the P5N32-SLI is straightforward; under the Advanced Options check into the CPU Configuration and turn off the AI Overclocking, which is Asus' built-in method of raising the speeds, by changing the setting to "Manual".  This allows the user to choose from a new menu called Performance Options.  It's on this screen that the most tinkering will be done.  Curiously, instead of entering in the CPU Clockspeed, as it appears to suggest that you should, the FSB Clock is entered.  For example, to manually enter the stock speed of the Pentium 4 550 CPU, you would enter in 800MHz (200MHz x 4).  It's a little too abstract, in our opinion, and could throw some users off as they are typically used to a range of 200-450MHz instead of 800-2000MHz.  If the clock mode is left as linked, the new memory speed will be displayed above the CPU speed, or this can be set to Manual which allows the user to manually enter both speeds, independent of each other.  Memory timings can also be set on this page, depending on whether or not the user wants to manually enter the timings or simply leave them to be determined by SPD.  Finally, the PCI-E frequency can be manually set to prevent the graphics card PCIe links from running too far out of specifications.  Running this too far off of expected speeds can easily disrupt the operation of most motherboards, so it's best to leave it at 100MHz. 

SANDRA CPU Results Overclocked to 3.99GHz	CPU-Z Details with CPU Overclocked to 3.99GHz	Memory Results Overclocked CPU, RAM @ 391MHz

We quickly ran through a number of speed checks, as our experience with this particular CPU has already limited our sights into the 230-240MHz range.  Our Corsair XMS2 memory fares well with overclocking, so we left the speeds linked.  We managed to quickly rise up to 225MHz (900MHz in the BIOS) before we had to bump the voltage for the CPU up to 1.55V, although as we mentioned earlier, this resulted in the CPU actually getting 1.45V.  The RAM we left at 2.1V, which is the best voltage for the pair of Corsair sticks we used in testing.  From there we continued on to 940MHz, or 235MHz, whichever works best for you, with the RAM operating at 391MHz on the memory divisor, which actually lists it as 783MHz (for sure this is an odd way to list memory timings).  This appeared to be the ceiling for overclocking on the PN532-SLI with our particular CPU, as any further attempts to raise the speeds and/or voltage would give us an "overclocking failed" message at POST.  As this fell into the range we expected, we decided to run a few benchmarks and call it a day.  Raising the CPU to 3.99GHz provided about a 15% increase in CPU performance.