On Gigabyte GA-M59SLI-S5 (F4 BIOS) you will find the following overclocking options:

• Base clock (HTT clock): Can be adjusted from 100 to 500 MHz in 2 MHz steps.
• PCI Express clock: Can be adjusted as auto or 100 MHz to 200 MHz in 1 MHz steps. This motherboard has separated adjustments for the two x16 SLI PCI Express slots (“NB_PCIE Clock”) and the other PCI Express slots (“SB_PCIE Clock”).
• HyperTransport clock (“NB<->SB Clock”): Can be adjusted from 200 to 500 MHz, from 200 MHz to 210 MHz in 0,5 MHz steps, from 210 MHz to 230 MHz in 1 MHz steps and above that in 2 MHz steps.
• CPU voltage: from 0.8000 V to 1.5500 V in 0.0025 V steps.
• Memory voltage: Normal, +0.1 V to +0.7 V.
• PCI Express voltage: Normal, +0.1 V, +0.2 V and +0.3 V. This motherboard has separated adjustments for the two x16 SLI PCI Express slots (“NB/PCI-E V”) and the other PCI Express slots (“SB/PCI-E V”).
• CPU to HyperTransport link voltage: Normal, +0.1 V, +0.2 V and +0.3 V.
• HyperTransport voltage: Normal, +0.1 V, +0.2 V and +0.3 V.
• HyperTransport Multipliers (see Figure 16).
• Memory timings (see Figure 17).

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Figure 15: Overclocking options on Gigabyte GA-M59SLI-S5 (F4 BIOS).

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Figure 16: HyperTransport bus options (F4 BIOS).

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Figure 17: Memory timings adjustments (F4 BIOS).

The PCI Express clock configuration is very important, as you can lock the PCI Express clock at a given value (100 MHz, for example). Usually when you increase the CPU base clock (HTT clock) you will automatically increase the PCI Express clock as well, and sometimes your overclocking will be limited not by the CPU but by the devices connected to the PCI Express bus. Thus with this option you can increase the probability of setting a higher overclocking. And this motherboard provides separated clock and voltage configurations for the PCI Express bus connected to the north bridge chip (i.e. the main SLI PCI Express x16 slot) and to the south bridge chip (i.e. all other PCI Express connections, including the second x16 PCI Express slot).

With this motherboard we increased the base clock of our CPU from 200 MHz to 220 MHz and the system worked just fine. We increased the processor voltage to 1.400 V and locked the PCI Express busses at 100 MHz and the HyperTransport bus at 200 MHz but we couldn’t reach a stable overclocking above 220 MHz (we only consider an overclocking successful if we can run PCMark 05 and Quake III three times without facing any problems).

The overclocking we achieved represents a 10% increase on the CPU internal clock, making our 2.6 GHz Athlon 64 X2 5000+ to run at 2.86 GHz. The performance measured by PCMark05 increased 6.91% with this overclocking.

On the other two socket AM2 motherboard we reviewed – ASUS M2N32-SLI De Luxe and ECS KA3 MVP Extreme – we were able to go up to 221 MHz, not so different from what we got with this Gigabyte model.