I received a number of emails requesting that I push the Dell to 3.0 GHz. I had some hesitation on this because I feel that this is a budget box where stability is paramount. In some instances, pushing the CPU to 3.0 GHz will not be as successful as the jump to 2.4 GHz - it's the nature of the beast. If you have to resort to increasing power and cooling for stability, you start to get into questionable (but fun!) territory considering this PC's inherent limitations.

However, with these caveats, I decided to show what might be possible if the stars are aligned just right.

A look at Intel's tech docs clearly shows how these CPUs control frequency¹. There are three pads that determine the CPU's frequency - BSEL 0, 1 and 2, located on the CPU as shown here (top view):

These three pads have eight possible combinations - only three are used:

The basic methodology for FSB changes involves the following:

• Shorting a pad changes a High value to Low
• Insulating a pad changes a Low value to High
• Shorting BSEL1 changes a 200 MHz FSB to a 266 MHz FSB
• Insulating BSEL2 changes a 266 MHz FSB to a 333 MHz FSB

Changing a 200 MHz FSB CPU to 333 MHz FSB therefore requires two changes - a "strap" to get to 266 MHz and insulating BSEL2 to go from 266 to 333 MHz²:

You can use tape or even paint over the BSEL2 pad to insulate it. Either way is reversible should it not work or prove to be unstable.

I used a small piece of scotch tape to cover BSEL2. The Dell budget box booted up no problem although it's clear that temps are higher but not dangerously so - running Prime 95 I now see temps in the low 50s, which is nowhere near a problem (ambient 20ºC). In normal use, if your CPU makes this jump at these temps and is stable, you should be OK.

Running Passmark Performance Test v6.1 at 3.0 GHz resulted in a benchmark of 836.0 vs 674.8 before the jump to 3.0 GHz - a 24% increase. Compared to where we started at stock settings (553.5), performance increased by 51%. Note that the CPU scores will scale with the FSB MOD ratio (333/266 = 25%; Passmark CPU 1636.6/1316.7 = 24.3%) - the Passmark benchmark is a combined score for all components tested and as such will not track 1:1.

As before, all settings are in sync - nothing is running out of spec except the CPU:

SiSandra CPU Benchmarks shows how far the jump takes us:

Overall the CPU in this budget box increased performance by 51% without any changes to cooling. The FSB increased a whopping 66.6% (333 from 200) with seemingly acceptable stability and CPU heat; while it worked for me and some others, pushing this CPU to 3 GHz is not a slam-dunk. Each user has to decide whether making these changes is acceptable considering who will use the PC and with what programs.

Personally I would not make the jump to 3.0 GHz for a "mommy" PC although I would not hesitate at 2.4 GHz.

¹"The BSEL[2:0] signals are used to select the frequency of the processor input clock (BCLK[1:0]). Table 16 defines the possible combinations of the signals and the frequency associated with each combination. The required frequency is determined by the processor, chipset, and clock synthesizer. All agents must operate at the same frequency."

²NOTE: Alternative mod to reach 333 FSB:

If covering BSEL2 does not work, the alternative is to connect BSEL1 to a VSS pad and connect BSEL2 to a VCC pad - two straps. VCC are the power pins for the processor and carry a positive charge and VSS are the ground pins for the processor and carry a negative charge.

If you have a 266 MHz CPU, you have only one strap - connect BSEL2 to the nearest VCC pad - this should give 333 MHz.

Email Joe