Question on FSB

[BlackDragon8303]

lately I been seeing the magic 200mhz FSB tossed around for some PIII's. Now I'm starting to get into tech and away from sales, but isnt a 200mhz FSB completely useless considering with PC133 ram (currently the fastest available with the exclusion of RAMBUS and the future DDR), creates a bottle neck problem, cutting down the FSB to only 133?

Also the FSB technically, is the speed of which the processors transfer information from themselves to the memory correct?

and also the DDR ram will be running at 200mhz? (100x 2) or will the option be able to go at 266? (133x 2) please shed some light thank you.

 

[kyoshozx]

200mhz for p3??? Hmm that probably would need you to submerge your whole motherboard into some super cooled liquid.

I think you're confused, when you overclock the FSB you're overclocking the memory also. The memory will be forced to run at 200mhz. If you're able to run your machine at 200FSB that means your pc133 ram is running at 200mhz. The ram will run at whatever speed the fsb is set at, or 3/4 the speed if its the via pro.
For example if you take a good old BX motherboard and actually get it to run at 200mhz, this would mean your ram is overclocked to 200mhz, it's no longer running at 100mhz.

Yes the FSB is the speed in which the processor transfer data from the main memory.

Also the fastest available ram is 150mhz, I believe it's made by kingston.

 

[snow patrol]

Also when you're overclocking the FSB, your overclocking the PCI and AGP bus...I find the prospect of the PCI running at 50mhz very unlikely..

Where did you see this?

 

[Packet]

I think you might have been reading about Athlon motherboards that run at 200mhz FSB. But I beleave thats only the chipset.

 

[OneEng]

The next generation Intel processor (code name Willamette) will have a 400Mhz FSB. The current Athlon family processors all have 200Mhz FSB. In the case of the Athlons, it is a 100Mhz DDR FSB, meaning that information is moved to or from the chipset on both the rising and falling edge of the system clock (which still runs at 100Mhz). The memory system, PCI bus, and AGP bus on Athlon systems run at normal speeds. Only the pathway between the chipset and processor has increased speed.

Willamette will transfer 2 times on the rising and 2 times on the falling edge of the system clock (which will still be 100Mhz).

The reason this is so important is that in many applications (3D games come to mind) much of the bandwidth of the chipset to processor bus is taken up by things like AGP information leaving no room for normal memory access. Since all information goes to and from the CHIPSET before it gets to the processor, any bandwidth used by one device takes away bandwidth from the others.

Current processors use L1 and L2 on-die cache memory to keep instructions and data that is frequently used close at hand to avoid the relatively slow main memory transfers. This has kept Intel's slow GTL+ bus alive so far; however, as processor become faster, more and more hits will occur on the main memory and a faster FSB will become much more important to overall performance.

As a final note, when DDR PC2100 memory becomes availible (basically PC133 memory that transfers on rising and falling edge) it will have the capability of transfering 2.1Gbytes/sec. This will require much more bandwidth from the FSB than the GTL+ bus has to offer.

 

[Goi]

Some chipsets allow the memory bus and the front-side bus(FSB) to be un-tied from each other, i.e. they run on separate clock speeds. Anyway, the memory bus and the FSB are 2 separate busses, it just so happens that they used to be always clocked together.

PCI/AGP/ISA overclocking due to increasing the FSB could potentially be a problem since they all derive their clock signals from the FSB currently. However, it shouldn't be hard to include new dividers that keep these busses/ports to their spec'ed speeds.