How does oc:ing affect your system?

[Zurxel]

Hi!
My first post and I got some questions for the wise overclockers dwelling here. I have read a lot on these forums and heave learned many things but there is still a few things I wonder about.

What I wonder is how does raising the FSB affect your system except for the effects on ram that has already been covered. What about the PCIe bus for example?

My second question is: What is HT? It's supposed to be around 1000 but what does it do and why can't it be much more than 1000?

I hope somebody can answer my noobquestions. Thx!

 

[Fern]

Hi Zurxel and Welcome to the Forums!

Here's a bump for you (I don't have a 64bit cpu so can't answer myself)

Fern

 

[DCypher]

bump

 

[clarkey01]

bump

 

[shira]

bump

 

[ts3433]

HT = HyperTransport, a point-to-point bus used by the A64s (though its use isn't limited to AMD). For 939 chips except the odd 939 3400+, it's only specified for operation at effective 1000MHz, and anything higher is unstable. 754 chips are 800MHz effective. To overclock the HTT (the A64 has no proper FSB, but this frequency affects things in the same manner), you need to lower the HT multiplier (separate from the CPU multiplier) at certain roadblocks. As long as the HT frequency stays between 600 and 1000, you shouldn't notice anything that will take away from your overclock.

I'm not sure exactly how it affects the PCIe bus.

 

[Jeff7181]

The PCI Express bus is locked just like the PCI and AGP bus.

HT is Hyper-Transport. It's a bus developed by MANY companies, not just AMD. Basically it's a high speed, narrow, low latency, bi-directional bus. I say narrow because it's 16-bits wide, and the FSB of processors since the original Pentium has been 64-bits wide. It operates at either 800 or 1000 MHz. Some places say 1600 MHz FSB... they're referring to the bi-directional 800 MHz HT bus. Because it's such a high speed bus, and because it's bi-directional, the total bandwidth is about the same, or slightly higher than Intel's 800 MHz FSB, but because it's such a low latency it performs better with the same total theoretical bandwidth.
It can't be much more than 1000 MHz because it's just not stable at speeds much higher than that... it has limits just like a CPU.

 

[Tiamat]

So, what you are saying is that if I were to have a hypothetical A64 939 processor and I wanted to reach 300mhz for my ram, I would not only have to watch my cpu multiplier, but also the HTT Multiplier as well?

 

[Gamingphreek]

No only if you change the HTT multiplier. Idealy it should be at whole numbers (Ie. not 2.5 or 3.5)

Also in order to achieve higher FSB results you may want to lower this as it will put a strain on the interconnect between the components.

-Kevin

 

[Zurxel]

Ok, thx guys. I think I get it now.

 

[gobucks]

i've had the HTT link up to 1200MHz before without any noticeable issues. right now it's at about 1100. just my $.02.