Does a higher fsb/htt help performance?

[Amd For Ever]

Does a higher fsb speed up your system or give any benefits if the cpu end result is the same? Like 250 fsb x 8 multi vs 200 X 10 multi. Does it give any benefit besides possibly speeding up the ram seeing as the pci express, and everything else seems locked? Has anyone found a way to oc the pci slots or anything else and wasn't unstable?
Would this give any extra performance?

 

[burningrave101]

If your talking about A64's and the HyperTransport link (HTT) then it does nothing to increase the speed and no you can't overclock the PCI slots because it would just make the system unstable if you could and it would also do nothing.

 

[Mnty9er]

Does a higher fsb speed up your system or give any benefits if the cpu end result is the same? Like 250 fsb x 8 multi vs 200 X 10 multi. Does it give any benefit besides possibly speeding up the ram seeing as the pci express, and everything else seems locked? Has anyone found a way to oc the pci slots or anything else and wasn't unstable?
Would this give any extra performance?

If you really want to push your system to the limit, you can try lowering the multiplier in order to raise the FSB even higher. In order to understand this, imagine that you have a 2.0GHz processor that has a 200MHz FSB and a 10x multiplier. So 200MHz x 10=2.0GHz. Obviously, that equation works, but there are other ways to get to 2.0GHz. You could raise the multiplier to 20 and lower the FSB to 100MHz, or you could raise the FSB to 250MHz and lower the multiplier to 8. Both of those combinations would give you the same 2.0GHz that you started out with. So both of those combinations should give you the same system performance, right?

Wrong. Since the FSB is the channel through which your system communicates with your processor, you want it to be as high as possible. So if you lowered the FSB to 100MHz and raised the multiplier to 20, you would still have a clock speed of 2.0GHz, but the rest of the system would be communicating with your processor much slower than before resulting in a loss in system performance.

Ideally, you would want to lower the multiplier in order to raise the FSB as high as possible. In principle, this sounds easy, but it gets complicated when you involve the rest of the system, since the rest of the system is dependent on the FSB as well, chiefly the RAM. Which leads me to the next section on RAM.

This is from the A64 overclocking sticky. Read it:
http://www.hardforum.com/showthread.php?t=795444

 

[Amd For Ever]

so even if you have the best oc ram possible it would be better to still use a mem divider (on a newer cpu like a A64) to get the highest possible fsb while not losing cpu speed as cpu speed is the most important? So system communication will still increase with a higher fsb even if the memory can't reach those speeds and everything else is locked? Thats why I don't understand how this would help your system. I understand if you go below 200 mhz you are bottlenecking your system but I thought only your ram is benefiting from the higher fsb assuming the end cpu speed is the same. What part of the system is running better then? Is there something behind the scenes that most people don't know about?

 

[the@ntipop]

While a high FSB won't hurt performance, on an Athlon 64 there are major diminishing returns on high FSB. So yes, it is much better to use a mem divider to get your CPU speed as high as possible while maintaing a stable memory clock. But increasing the HTT higher than your FSB speed doesn't do much (if anything) to help you. If you are at your maximum CPU multiplier, though, it will be the only way to increase overall CPU clock speed.

 

[burningrave101]

While a high FSB won't hurt performance, on an Athlon 64 there are major diminishing returns on high FSB. So yes, it is much better to use a mem divider to get your CPU speed as high as possible while maintaing a stable memory clock. But increasing the HTT higher than your FSB speed doesn't do much (if anything) to help you. If you are at your maximum CPU multiplier, though, it will be the only way to increase overall CPU clock speed.

There is no FSB. There is only a HyperTransport link and its the link between the CPU and the chipset. Overclocking the HTT wont gain you any performance. Overclocking the RAM will only give you small increases in performance. Overclocking the CPU speed is all that really matters. When you overclock the CPU you also overclock the integrated memory controller as well.