Memory bus and FSB

[roberd]

Have I got it right:
1. the memory bus is a connection between the chipsets north bridge
and the memory
2. if the memory bus is operating at speed 133MHz, the data
is moving at that speed from memory to the chipset and vice versa
3. FSB (Frons Side Bus) is the connection between the chipsets north
bridge and the processor
4. if the FSB is operating at 100MHz, the data is moving
at that speed from the chipset to the processor (and vice versa)

If all this is correct then I have a question. I am runnng my computer
at 100MHz FSB and 100MHz memeory bus. How much faster would my computer
operate (in percentage) if I set the memeory bus to 133MHz? Assume the
memory modules to be CL3 with both speeds?

If there was something wrong with my assumptions, please correct me.

[diurnal]

FSB is basically the connection between the processer and the whole cpu(buses).You would probably not tell a big difference between 100mhz and 133 Mhz, however if you run tests you might see a slight improvement.You would definately see a difference with the new ddr ram which basically can runs at 133 too but the memory is faster.The memory runs at 266MHZ however your still hampered by the motherboard speed which still runs at 133mhz.If you do increase your memory speed , you would probably need to buy a stick of pc133 ram, so it will be stable.Also if you do up the speed of your memory make sure to watch your cpu temps because it will increase as well, forcing you to get a bigger heatsink fan for your cpu.This forum is not intended for overclocking and other forums would be more able to help you in your situation. Go here http://www.overclockers.com/ and they should be better able to figure your question out.

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Sledgehammer will save the day!

[roberd]

I made myself unclear in my posting. I do not want to overclock my
computer. I am only wondering if my assumpitions were right. I have
read that the proseccoer is directly connected to the memory bus.
On the other hand my understanding is that both the memory bus and
the FSB in is connected to the chipset. Does anybody know which way it is?

[iisbob]

If you're using a VIA chipset, then yes-the northbridge is the connection between your CPU, memory and PCI ( which includes the AGP )-you want to be careful increasing your FSB, as the PCI slots, and the AGP in particular, get very cranky.

If you have a newer Athlon system ( 200/266 ) you actually still have a FSB of 100/133-it's just " doublepumped ". IE a 266 FSB Athlon is actually a 133 FSB where the data is being fed twice.

On the newer SIS735 chipset that i have ( k7s5a ECS DDR Board ) both the n/s bridges are in one chip-immeasurably increasing overall system speed, i've seen a better than 25% improvment over the VIA chipset i had.

The PCGuide (http://www.pcguide.com/ref/mbsys/buses/index-c.html) has an excellant guide on the systembus.

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iisbob
"640K ought to be enough for anybody. - Bill Gates, 1981"
"Imagination is more important than knowledge. Knowledge is limited. Imagination encircles the world." --Albert Einstein (1879-1955)

[roberd]

Thank you vey much. Case closed.

[kenja]

The case is closed, but I can't resist replying. http://www.PCGuide.com/ubb/smile.gif "Have I got it right"...yes. I have a VIA chipset motherboard that allows the memory bus to run 33MHz faster than the FSB. The SiSoft Sandra 2001 memory benchmark score is nicer, but I can't really detect a real-world difference.

[roberd]

Allright, reopened http://www.PCGuide.com/ubb/smile.gif I checked the charts of the VIA KT266A, AliMAGIK 1 and AMD-760 chipsets. All of those chipsets memory buses are connected to the north bridge. I think all this is a bit confusing because I have read from various sites that the processor is directly connected to the memory. This would obviously mean that the data from the memory is not transfered through the FSB!