Core i7 Platform Configuring

Since new Core i7 processors change the platform architecture we need to talk a little more about the way these processors get configured in the mainboard BIOS Setup, especially since this CPU may seem not so easy to configure to some users. We are going to discuss the configuration specifics using the BIOS of the above described Intel DX58SO Smackover mainboard as an example.

The main system parameter affecting the frequencies of almost all system components is the frequency of the clock generator called Host Clock Frequency. It can be set in the first screen of the Performance section. By default it is set at 133MHz, however, the board allows increasing it up to 240MHz.

Processor parameters can be configured on Processor Overrides page of the Performance section.

It starts with three options for CPU voltage management. You can set absolute and relative voltages and enable special mode reducing negative Vdroop effect (the drop of the voltage from the processor regulator occurring during current increase).

Then you can adjust the default clock frequency multiplier applied to clock generator frequency to obtain the CPU frequency.

The next big group of parameters is devoted to management of Turbo Boost Technology or Intel Dynamic Speed Technology in the BIOS terms. Since it is implemented via a special PCU microcontroller built into the processor, there is a lot to play with here. You can “edit” the processor TDP and maximum allowed current values used by the PCU, enable or disable automatic Vcore increase and set maximum clock frequency multipliers when the processor works with different number of active cores. However, you will be able to play with the multipliers only if you have an Extreme Edition CPU.

According to the turbo-mode specification, if the CPU utilization at a given moment of time allows increasing its frequency without getting beyond the set heat dissipation and power consumption limits, then Core i7 processors can increase their multiplier over the nominal. One step over the nominal if there are 2, 3 or 4 active cores, and two steps over the nominal if there is only one core active. However, as you can see from the available settings, this technology can do much more than that, as all of its key parameters can in fact be adjusted. Namely, overclockers who have a Core i7 Extreme Edition processor with an unlocked multiplier will be able to adapt Turbo Boost Technology for their needs. You can configure the PCU for very aggressive management of the CPU frequency, when its power consumption even goes beyond 130W.

Memory Configuration page is devoted to memory subsystem settings.

First of all you should pay attention to the way the memory frequency is set. It has a multiplier of its own applied to the clock generator frequency to obtain the DDR3 SDRAM frequency. With the supported multipliers ranging from 6 to 12 you can use memory working at 800-1600MHz. There is also a UCLK multiplier setting the operational frequency for the "un-core" interface components, such as built-in memory controller, L3 cache and QPI bus controller. This multiplier has to be at least twice as big as the memory frequency multiplier. Its further increase does improve the performance even more, but has a negative effect on the memory subsystem stability.

Here you can also adjust the memory voltage. Note that Intel strongly recommends not to push this parameter beyond 1.65V, because it may damage the memory controller built into the CPU. As a result, the systems based on Core i7 processors will have very limited ability to use previous-generation high-speed DDR3 memory. This memory required higher voltage than the 1.5V assigned by the standard in order to work at its nominal speed. Luckily, this problem can be solved in the new DDR3 SDRAM modules that are built with the chips working at high frequencies with their voltage setting close to 1.5V. Most makers of enthusiast memory kits have already released their solutions of the kind.

The most interesting thing on the Bus Overrides page is the QPI bus settings.

BIOS allows changing its frequency and voltage. Both these options may be very useful when you overclock the processor by raising the host generator frequency. Moreover, you may need to increase QPI voltage if you set a high multiplier for processor interface components.

Besides the above mentioned settings and parameters, you may also need to enable or disable SMT technology in the BIOS. It is available on the first BIOS page.

There is one more setting next to it that allows disabling two or three processor cores turning Core i7 into a dual-core or single-core CPU respectively.

You can configure power-saving technologies and Intel Enhanced SpeedStep in the Power section.

All other options that you can find in the Intel DX58SO mainboard BIOS are pretty common so we will not dwell on them in our today’s article.