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| Examining the BIOS of the SB95P |
| The "setup" for our setup |
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Shuttle used the ever-popular Phoenix / AWARD BIOS for the SB95P, which was fully stocked with options for controlling each and every aspect of operation. The SB95P supports not only IDE and SATA drives, but will allow for SATA RAID configurations as well, using the ICH6R chipset. In other words, the SB95P could support an IDE hard drive, as well as two SATA drives running in RAID0, something commonly seen in full-size systems.
Most other options were standard stuff, such as picking a boot order for the drives, and whether or not the on-board audio, LAN, and Firewire ports are to be enabled. Under PC Health, fan speeds, voltages, and temperatures are monitored. Users can select whether or not to run the fans at percentages of the maximum speed, or leave it on 'Smart Fan' and have the system automatically decide what is best at that moment. In the last section, Frequency and Voltage Control, the SB95P can be tweaked a bit to squeeze out a little more performance. DRAM timings can be left at By SPD, which will detect the timings using Serial Presence Detect registers on the memory. These can also be manually lowered to improve performance somewhat, although finding timings that work can sometimes be a chore. Finally, there's some options for changing the CPU Speed as well as CPU, DDR, and Chipset voltages, which are covered in the next section.
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| Overclocking Tools |
| An Overclocker's Delight! |
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At first glance, the SB95P seems ready for overclocking. The CPU front side bus speed can be set anywhere between 100MHz and 355MHz, and there's even an option to lower the multiplier from the default value (in this case 17x) to 14x for high-end Prescott CPUs, which in some cases could allow for higher overall FSB speeds. Omitted from this section of the BIOS, however, was any way to lock down the PCI-e clock, which could spell doom for severely high overclocked speeds. For each change we make to the FSB to increase the CPU speed, we're also raising the speed of the PCI-e link as well. Voltage options were OK for the CPU, reaching a ceiling at 1.5875V, which should be enough for the speeds we intended on hitting in an SFF PC. DDR2 Voltages can be set at Auto, 1.8V, 1.85V, and 1.9V and the ChipSet Voltage also has four options as well for Auto, 1.55V, 1.66V, and 1.70V.
SANDRA CPU Benchmark
PCMark04 Benchmark
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Since this was the first time we had overclocked this particular P4 550 3.4 GHz CPU we weren't exactly sure how far we would get. Some CPUs just do better than others for various reasons, and you're never quite sure until you get your hands dirty. We quickly moved up to the 230MHz FSB range without any problems, and this only required some slight adjustments on the CPU and DDR2 voltages. We were not able to get much further than this, however. Booting into Windows was possible at 235MHz, but benchmarks would not complete. 240MHz resulted in a complete lockup at during POST and forced us to clear the CMOS to try again. This was tried at both 14x and 17x mulitpliers with the same result. It looked as if the lack of ability to lock down the PCI-e bus might be holding us back, but it turns out that we got the same overclocking results on the Epox 5LWA+. Thankfully, Shuttle has included a 'Clear CMOS' button right on the back of the SB95P, which made resetting the BIOS much easier than previously possible.
Our final stable overclock came out at 232MHz, a modest increase in overall speed equalling about a 16% jump in speed. As seen in the SANDRA and PCMark04 screen captures on the left, we were running just shy of 4GHz (232MHz x 17). The increased FSB improved not only our CPU performance, but the memory as well, as it was now running at close to 310MHz. Our new score in SANDRA was well beyond our original results, and was able to outpeform a 3.6GHz Pentium 4 in SANDRA's database. Additionally, the PCMARK04 results we got while overclocked were 13% better for the CPU peformance and 15% better for the memory. |
