Tweaking Optimizing Windows.pdf - GEGeek

are much easier to use. No matter who makes your mainboard, be it Abit, Asus, Soyo, MSI, most BIOS do offer overclocking
features - look out for them :)
The bus speed refers to the actual motherboard and it's components. They also run in Mega-Hertz (Mhz) and they all run together
at different dividers, or fractions of the CPU speed. Your motherboard has traces on it, if you look down at a motherboard and you
see all those long lines running all through it to different components that is the bus of the motherboard, data paths to all the
components. The Front Side Bus (FSB) by definition is the bus that connects the processor (CPU) and the main Memory (RAM).
The PCI bus is the bus that connects all the PCI devices (connected to the PCI expansion slots), as well as the I/O Controller for
your Hard Drive and CD-ROM. The AGP bus is the bus that your AGP video card runs on from the AGP slot. These are the main
buses you have to worry about when overclocking. Other types of buses, such as SCSI are also affected by overclocking, but they're
beyond the scope of this article, besides they are generally affected by the PCI/ISA bus.
How this all fits together: It takes the FSB speed (which is also the RAM speed don't forget) multiplied by the CPU Multiplier to
create the CPU Internal Clock speed. For example a FSB speed of 100Mhz times a multiplier of 8 will equal 800Mhz, that is
expressed like this: 100 x 8 = 800. Simple as that. The 3 Official FSB speeds currently are 66Mhz, 100Mhz, and 133Mhz. In order
to get other bus speeds and try to get different Internal CPU speeds, your motherboard needs to have more FSB option settings, we
will go into more detail a little later. Keep in mind when you do overclock the FSB you are overclocking your memory (RAM) so if
you have some modules of some slow cheap pieces of memory they may not like to be overclocked at all. If you buy good brand
name memory like Corsair, Mushkin, Micron, Infeneon or Samsung, you will have a much better chance at overclocking your FSB.
You also need to know the speed in Mhz of the other buses in your PC. This is because when you raise the Front Side Bus (FSB)
you are also raising all the other bus speeds. The PCI bus officially runs at 33Mhz, you need to keep it as close to that spec as you
can, because overclocking it to high might cause one of your PCI components not to operate correctly. It works like this, in order to
get the PCI bus at 33Mhz at a 100Mhz FSB you would use a divider of 1/3 It's expressed like this 100 x 1/3 = 33.3 which is 33Mhz.
These divider settings are set in your BIOS, or by jumpers on your motherboard, if at all possible (you might want to check your
motherboard's manual for additional info). Now lets say we wanted to raise the FSB to 133Mhz if we kept a divider of 1/3 the PCI
bus would be running at 133 x 1/3 = 44.3Mhz this is way too high and devices attached to your PCI bus may not work at this
setting. So what do you do? Change the divider setting, most new motherboards that officially support the 133Mhz FSB have a
divider setting of 1/4 you can use, 133 x 1/4 = 33.25 or rounded to 33Mhz which is back on spec.
The next bus you have to worry about is the AGP bus. The AGP bus, as you recall, is the bus that your AGP Video Card runs off of,
so the only device you have to worry about overclocking is the bus that the video card is plugged into. The AGP bus runs at 66Mhz,
so no matter what you do when you overclock try to keep it as close to 66Mhz as you can and you won't have any problems with
your video card. Now most newer video cards can take a high AGP bus setting, I've seen some go as high as 100Mhz and most
make it to 88Mhz but for first time overclockers I recommend that you try to keep it as close to 66Mhz as you can. The AGP bus
uses dividers just like the PCI bus.
At a 100FSB you have to use a divider of 2/3 it's expressed like this 100 x 2/3 = 66.6 or 66Mhz. If you were to raise the FSB to
133 and keep the 2/3 divider you would have an AGP bus of 133 x 2/3 = 88Mhz. In order for it to get back to normal you would
have to use a divider of 1/2 now this is a problem on all Intel BX chipset motherboards because they only go up to a 2/3 divider,
there is no 1/2 divider, and anything over the 100Mhz FSB speed will mean overclocking the AGP bus speed as well.
Again, when increasing your FSB speed, you'll also have to consider all the other devices in your system. Just because the CPU runs
stable at the higher speed settings doesn't mean you have overclocked successfully. Any of the other devices can stop functioning
or start causing problems. You might need to edit your CMOS and lower some of the settings for the RAM and/or Hard Drives to get
your system functioning without problems. It is a fact that by overclocking you increase the chances of system faults, crashes and
overall instability, so if avoiding a crash is crucial, consider buying faster Processor or components, rather than overclocking.
Just remember for reference:
PCI Bus
= 33Mhz
AGP Bus
= 66Mhz
FSB x Multiplier
= CPU Internal Clock Speed
FSB x Divider
= PCI or AGP Bus Speed
Effect of non-standard bus speeds
Non-standard bus speeds can have a variety of effects on various types of computer hardware. Hard drives can miswrite data, CD
writers can create even more coasters than usual, CD-ROM drives can refuse to function, RAM can refuse to work properly, etc.,
etc., etc. Some of these problems can be fixed by adding some rudimentary cooling, but many of them are simple limitations of the
hardware which will limit a system's overclockability. Keep an eye out for these things because they can cause serious problems
with a system. Most of these problems occur when using bus speeds that exceed the PCI bus frequency. PCI is intended to run at
33 MHz. If you set it to ove 40 MHz or so (using 83, 124, or 133+ MHz bus), there is a fair chance your hard drive will lose
everything. See page 3 of the Hard Drive Tweak Guide for more information.
FSB limitations and agp clock speeds
As processor quality increases overclockability, overclockers are finding themselves running Front Side Bus(FSB) speeds that are
farther and farther above spec. Ironically, the "old" BX chipset is often the platform of choice for many because it still offers the
highest clock-for-clock performance of any other chipset. Often, processors such as the PIII-550e are able to run at speeds in
excess of 800MHz. Running at this speed results in an FSB speed often greater than 145MHz. The BX chipset is only designed to run
with a 100MHz FSB or lower. When running at its maximum rating of 100MHz, the BX chip only has to divide the FSB by 2/3 to
achieve the proper 66MHz operation in the AGP slot. As the FSB increases, this 2/3 multiplier results in higher and higher AGP bus
speeds, creating more strain on the video subsystem. At 145MHz FSB, the AGP slot is running at 97MHz!!! That is nearly 150% of
the 'rated' speed. Most video cards cannot tolerate this increased speed and will not run.
Some of the newest cards, notably the GeForce line from nVidia and the Radeon from ATI, have been able to tolerate this speed on
occasion. While running significantly over 90MHz on the AGP bus is still a stretch, a majority of these cards will run the 89MHz bus
required to support a 133MHz FSB on the BX platform. This is a much more common overclocked speed, as the BX does support a
1/4 PCI divider, leaving the PCI perfectly in spec (33MHz) while the FSB is at 133MHz. If the AGP card only shows mild instability at
the overclocked speed, a small increase in the IO voltage (only supported by some motherboards) can increase stability. If you are
having extreme difficulty finding an AGP card to run with a high FSB, or if you want to use a greater than 150MHz FSB, you have