166 Bus Speed?

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Originally posted by Shiranai_Baka+30 December 2003 - 11:02--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (Shiranai_Baka @ 30 December 2003 - 11:02)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin-james_bond_rulez@30 December 2003 - 19:22
fsb is not the bus speed

if you see figures like 200/266/333/400 front side bus speed on the mobo (supported speeds) the bus speed is 100/133/166/200, dont confuse them

also the overall clock is determined to multiplying the multiplyer of the cpu and the bus speed

so amd 2600+ has a multiplyer of 16 times the bus speed of the mobo 133, gives 2.13Ghz system clock

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Thanks james bond. (And my mobo can run at 400FSB) [/b][/quote]
no, ur mobo may support 400fsb but ur cpu can only run at 166Mhz bus speed maximum

going over that speed should shorten ur cpu life considerably

i wouldn&#39;t waste a good cpu like that if i were u

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Originally posted by james_bond_rulez@30 December 2003 - 20:09
no, ur mobo may support 400fsb but ur cpu can only run at 166Mhz bus speed maximum

going over that speed should shorten ur cpu life considerably

i wouldn&#39;t waste a good cpu like that if i were u

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why can the cpu just run at 166 and not 333? just wondering cuz im confused.... i got an athlonxp 1800+ and had to set it to 133.... but why is it double?

Front side bus
From Wikipedia, the free encyclopedia.


Front-Side-Bus (FSB) is an Intel term describing a CPU-to-system memory data bus. It has been formerly known as CPU bus speed, external CPU speed, memory bus and system bus, too. It is the speed at which the CPU communicates with RAM (memory).

Many system components - including the PCI and AGP buses - run at speeds derived from the frontside bus speed. In general, a faster frontside bus means higher processing speeds and a faster computer.

How fast your processor runs at is determined by applying a clock multiplier to the frontside bus speed. For example, a processor running at 550MHz might be using a 100 MHz FSB; this means there is a clock multiplier setting of 5.5, thus the CPU is set to run at 5.5 times the MHz speed of the front side bus: basically equating to 100 MHz x 5.5 = 550 MHz.

Most motherboards offer the ability for the user to manually set the clock multiplier and FSB settings by changing jumpers. Although many CPU manufacturers now usually "lock" an unchangable preset multiplier setting into the chip, meaning manually-set multiplier settings are ignored in favour of the preset multiplier. It is possible to unlock some locked CPUs (namely those from AMD) through a complicated process of connecting electrical currents across points on the CPU&#39;s surface.

For some processors, the FSB speed can be increased to boost processing speed (called overclocking). This overclocking can take different forms; such as overclocking the front side bus higher than the motherboard was designed to go, or overclocking the front side bus for the purposes of overclocking a (usually, locked) CPU.

The PCI and AGP buses, which usually run much slower than the frontside bus, use dividers to reduce the clock speed. Typically the PCI bus runs at 33 MHz, and the AGP bus runs at twice the PCI bus&#39;s speed. The speed at which the PCI bus is set at is a division of the front side bus&#39;s speed: eg, a 166 MHz front side bus will mean the PCI bus is set to run at 1/5th of the speed of the FSB. Usually a motherboard will have FSB speed increments at which these PCI dividers are designed with: typically 66 MHz, 100 MHz, 133 MHz, 166 MHz and 200 MHz; meaning dividers of one half, one third, one forth and so on, to go with the standard bus speeds. When a person overclocks or just increases the front side bus speed away from one of the normal speed increments, the PCI bus (and AGP bus + the hard drive controller) will therefore be overclocked too: eg if Joe increases the front side bus from 100 MHz to 105 MHz, the PCI bus will then be at 35 MHz and the AGP at 70 MHz), because it is still retaining the ratio meant for the 100 MHz bus. Changing the FSB all the way to 133 MHz will swap over to a 1/4th ratio for the PCI bus, and therefore it will be similarly overclocked if the FSB is moved to 138 MHz.

When choosing a FSB speed for the CPU you chose, be aware that you&#39;ll need to purchase memory capable of this faster speed. Pushing the front-side bus to 110 MHz means you are also pushing your memory, be it PC100 (or higher, i.e. PC133), to 110 MHz. Some PCI devices (such as sound cards) won&#39;t handle the PCI bus going too far above the default speed. Sometimes hard-drive controllers will behave incorrectly in such environments too.

In a typical image processing application where the data set (acquired images) is large, FSB speed becomes a major performance issue. A slow FSB will cause the CPU to spend significant amounts of time waiting for data to arrive from system memory.

One issue of confusion is the labeling of front side bus speeds. Typically a FSB today is dual or quad channel, meaning a FSB speed advertised as being "333 MHz" may actually be 166 MHz dual channel, effectively meaning 333 MHz of speed. Nowadays, PC (X86) CPUs work with front side bus speeds ranging from 133 MHz dual channel (266 MHz effective) to 200 MHz quad channel (800 MHz effective).



The back side bus goes to the L2 RAM cache and has always been faster than the front side bus which goes to main RAM and the rest of the system.

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Originally posted by DWk+30 December 2003 - 18:16--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (DWk @ 30 December 2003 - 18:16)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin-james_bond_rulez@30 December 2003 - 20:09
no, ur mobo may support 400fsb but ur cpu can only run at 166Mhz bus speed maximum

going over that speed should shorten ur cpu life considerably

i wouldn&#39;t waste a good cpu like that if i were u

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why can the cpu just run at 166 and not 333? just wondering cuz im confused.... i got an athlonxp 1800+ and had to set it to 133.... but why is it double? [/b][/quote]
same thing really

166Mhz dual channel really meant 333Mhz FSB

:lol:

so yeah running that cpu at 166Mhz dual IS running at 333 Mhz FSB ;)

oh ok....thats waht i thought before...just checking it hehe....


btw this makes me laugh so much

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It is possible to unlock some locked CPUs (namely those from AMD) through a complicated process of connecting electrical currents across points on the CPU&#39;s surface.

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yea i bet the pencil trick is 2 complicated.... i bet only "certified technicians" can do that hahahah

so ram also runs at that (ddr of course).... like at 133 instead of 266 and 166 instead of 333?

the pencil trick is a cheap solution....

i use something more expensive to unlock my old amd.... :lol:

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Originally posted by DWk@30 December 2003 - 18:28
so ram also runs at that (ddr of course).... like at 133 instead of 266 and 166 instead of 333?

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yeah check ur ram to make sure it&#39;s always equal or higher than the system bus is designed to run ;)

otherwise u&#39;ll have the bottleneck effect....

nah its cool thats not the problem.... im just trying to learn shit hehe

The &#39;multiplyer&#39; refers to the fact that all procs since the intro of the pre-Pentium 486 class (they were clock doublers-i.e. 486 dx2/66 or 33mhz outside speed and 66mhz internal core). The old mobos were locked at 33mhz bus but the core ran at 66mhz. This allowed for faster procs while sticking to the old mobos. Now, of course, we&#39;re hitting 600mhz Front Side Bus speeds on P4s and 400 on Athys. The proc always runs faster at core than the FSB. Why? Radio Frequency Interferance (RFI) and cost, among many other matters. Besides, the core spends more time on internal calculations than talking to the address bus, so it&#39;s cool if it&#39;s faster than the bus-though God knows it&#39;s one hell of a bottle neck .

My old Athlon 1200 (not XP), for example, had a multiplyer of 9 at 133mhz (mobo)with a system bus of 266Mhz for 1.2Ghz or there abouts. It&#39;s core voltage was 1.75 volts. By raising the FSB, you can increase the core speed on procs that are multiplyer locked (Pentiums, for example). This stresses the whole system so it&#39;s best to up the multipyer. You&#39;ll have to increase core voltage also, as it&#39;ll need more juice to run at higher speeds. It&#39;ll also get hotter than hell fast, so cooling is a must. Most, if not all of this should be in the mobo&#39;s soft BIOS or jumpered on the mobo itself. You&#39;ll need the manuel smurfette was so kind as to provide. It&#39;ll have the details.

Do all this slowly. Try it a little at a time. Make sure it POSTs and runs stable for extended periods. Each proc is different. Some will go up big time, some won&#39;t, even if it&#39;s the same model.

Keep in mind that over clocking voids your proc warenty if you try it and shortens the life span of the proc. You will also have to make alterations the CPU itself, though I cnat remember the specifics on your proc. Either of these can KILL your proc. I&#39;ve seen it. Nasty.

Note: The FSB is the connection between the CPU, the chipset (VIA. nForce, Intel etc.) and RAM. The BSB, or Back Side Bus is between the proc and it&#39;s L2 cache. The rest is the external data bus and address bus.

Here&#39;s a link to try. This site is devoted to voiding the warrenty on your proc without burning it in the proccess. OverClockers.com. For more general info, try TomsHardware.com or just hit trusty old Google. Hope this helps at least a little and thanks ahead of time for the corrections of any accidental errors I might have made&#33; :D ;)