Shuttle SB77G5 - i875 LGA775 Socketed XPC

The FB77 motherboard that the SB77G5 is built upon, is equipped with an Award BIOS version that we've all come to know and love over the years.  All the features and tweaks you would expect to see in a full sized system implementation, can also be found in the SB77G5's menu options.

The BIOS: Shuttle SB77G5 XPC Standard Issue Award with all the trimmings

There's a good range of ability to tweak bus and interface speeds, as well as manipulate various voltage settings, should you want to try your hand at overclocking.  CPU FSB settings of up to 355MHz should allow for "unofficial" support of Intel's latest 1066MHz (266X4) FSB Pentium 4 Extreme Edition processors and we'll show you more on that in the follow overclocking section here.  There are also DDR266 (a 3:2 divider ratio) DDR320 (5:4) and DDR400 (1:1) settings, which allow the end user to manipulate FSB speeds to accommodate RAM speeds, keeping them within a reasonable range of their specs in conjunction with an overclock of the CPU.  Voltages settings are available in .125 volt increments for the CPU and  .1 volt increments for system memory, however we would have liked a bit more high end settings beyond 2.9V for the memory options, even though it is admittedly rare that voltage levels that high are required for stability.

Then there's the "secret sauce" that Shuttle employs to keep the SB77G5 and many others in their XPC line-up cool and quiet during operation, "Smart Fan" and "CPU Temp Tag".  Smart fan automatically adjusts fans speeds according to the CPU Temp Tag setting in the BIOS.  Then, depending on the number of degrees over the CPU Temp Tag setting, the fan will adjust its speed from 950 RPM to over 2100 RPM, in order to compensate for the added heat build up.  We found this feature to be a really nice tool in striking that all important balance between acoustics and system or CPU temperature control.

Overclocking The Shuttle SB77G5 XPC A hot little Prescott in a small box - 1066MHz FSB Capable?

Our efforts in overclocking the SB77G5 were met with impressive results, although frankly we didn't go into this experiment expecting all that much from such a little enclosure housing Intel's 3.6GHz Prescott CPU, which we've come to discover runs just a tad hot under the collar.

CPU @ 3.92GHz

Multimedia @ 3.92GHz

Memory @ 436MHz

However, with a little finesse, a 1.4V CPU core voltage setting and a 2.9V setting for our RAM, we had the SB77G5 running at a stable 3.9GHz CPU speed and our Kingston DDR memory at 436MHz, although we had to set the fan setting in the BIOS to "mid" in order to keep heat in check.  This was a 2100 RPM fan speed setting and the resultant noise was completely tolerable but a lot less stealthy than while in "Smart Fan" mode.  Our Prescott 3.6GHz processor, running at 3.9GHz, hovered in the 65^oC range, which is a bit on the warm side but things were stable regardless.  We were more than impressed at the SB77G5's ability to overclock, so we decided to look at one more experiment, from a different angle, that of at 1066MHz front side bus speed.  A ghost of things to come perhaps?

P4 3.6GHz Prescott
At 3.73GHz - 1066MHz FSB

We thought it would make sense to look at an optimal setting for a processor, like the 3.46GHz P4 EE or the upcoming 1066MHz FSB Prescott with 2MB of L2 cache, that Intel is rumored to be unleashing in Q1 of '05.  So, with that in mind, we took the divider of our 3.6GHz Prescott core, down to 14X from 18X and bumped the system bus speed up to 266MHz, which yields our 1066MHz FSB.  With a DDR320 divisor setting in the BIOS, our memory was clocked in at 425MHz and the CPU was set at 3.73GHz with its 14X multiplier on a 266MHz bus.  Things were very stable at this speed and it helped lend proof that the SB77G5 should by all rights, unofficially support 1066MHz FSB based Pentium 4 processors moving forward.  We contacted Shuttle on this topic and they gave us the standard issue that the 1066 FSB Pentium 4 CPU is not "officially" supported at this time but off the record we got a wink and a nod. That's good enough for us but you'll be running things at your own risk of course.  Nothing like a global "cover-your-butt" statement which is always the case in matters of overclocking!