'HT' what is it?

Hapkido · Post by **Hapkido** » Thu Feb 08, 2007 4:59 pm

Thanks to the help of "HONkUS" I have been very successful in overclocking my AMD 64 X2 4200+ to a stable and respectable 2.7 Ghz. So now that I feel relatively comfortable overclocking, my interest is now upon the various elements that one changes in the BIOS to actually do the oc. Specifically, I'm interesting in knowing about "HT". To increase the "HTT" (FS Bus) more than 135 I had to reduce the size of the "HT" from the default 5x to 4x. Why? This is what I'm wanting to know, i.e., what is the relationship of this "HT" to the other elements? How does it effect, if it does at all, e.g., RAM timing, HTT, etc.?

Thus I would be much appreciative if someone could enlighten me a bit about "HT" and/or point me to an article which could do so.

THANKS!

kenc51 · Post by **kenc51** » Sat Feb 10, 2007 8:43 am

"HT" is the Hypertransport bus.
A "bus" is just a pathway for information to flow (PCI & AGP are other kinds of buses). The hypertransport bus is how an AMD CPU communicates with the memory and other parts on the motherboard.
The HT bus (link) is very fast! Since the HT link is used to carry data for just about everything on the board, it must have a good signal at all times. When you overclock anything the signal can degrade, this is why we add more voltage to stabilise things.
When you overclock your CPU your also overclocking the HT link and this causes instability. So if you lower the base speed of the HT link you can overclock the CPU more. The CPU link to HT is independent, so changing the HT multi from 5x to 4x doesn't effect the CPU speed.

So when running 5x your max is normally 230MHz. You should always try to keep the HT link between ~850 & ~1GHz for best performance.

I'm running my link at 1300MHz (260x5) btw

Hapkido · Post by **Hapkido** » Sat Feb 10, 2007 10:30 am

Perfect!!

Thanks, that's what I wanted to know. BTW, my HT is currently 920 MHz which according to your information is just about ideal.

kenc51 · Post by **kenc51** » Sat Feb 10, 2007 11:06 am

"Share the wealth" That's my moto!

That's what LRForums are all about! ;)

camaroguy1998 · Post by **camaroguy1998** » Sun Feb 11, 2007 12:05 pm

kenc51 wrote:"HT" is the Hypertransport bus.
A "bus" is just a pathway for information to flow (PCI & AGP are other kinds of buses). The hypertransport bus is how an AMD CPU communicates with the memory and other parts on the motherboard.
The HT bus (link) is very fast! Since the HT link is used to carry data for just about everything on the board, it must have a good signal at all times. When you overclock anything the signal can degrade, this is why we add more voltage to stabilise things.
When you overclock your CPU your also overclocking the HT link and this causes instability. So if you lower the base speed of the HT link you can overclock the CPU more. The CPU link to HT is independent, so changing the HT multi from 5x to 4x doesn't effect the CPU speed.

So when running 5x your max is normally 230MHz. You should always try to keep the HT link between ~850 & ~1GHz for best performance.

I'm running my link at 1300MHz (260x5) btw

If 850-1GHz is optimal performance , how did you manage to get yours to 1300(260x5) and is the difference noticeable?

kenc51 · Post by **kenc51** » Sun Feb 11, 2007 12:10 pm

My motherboard uses the RD580 chipset ;)
I haven't tested if it gives more peformance though, but I have tested it stable upto ~280x5 (1400)

I'd say it would only help with 3Dmark.......no real world performance!

camaroguy1998 · Post by **camaroguy1998** » Sun Feb 11, 2007 12:18 pm

kenc51 wrote:My motherboard uses the RD580 chipset ;)
I haven't tested if it gives more peformance though, but I have tested it stable upto ~280x5 (1400)
I'd say it would only help with 3Dmark.......no real world performance!

Ok, I see your sig says your using a 3800 X2, what mobo are you using?

kenc51 · Post by **kenc51** » Sun Feb 11, 2007 12:21 pm

ASUS A8R32-MVP Deluxe
One of the best motherboards I've ever had! Very stable and easy to setup.

Sig edited ;)

kenc51 · Post by **kenc51** » Sun Feb 11, 2007 2:06 pm

Just done some testing with HT speeds and 3DMark 05

HT set to 1052MHz

HT set to 1315MHz

Differnce is only 20pts! This shows there's no benefit from going over 1GHz!
Only the HT multi was changed between runs!