Can some explain HTT??

[nealh]

I just do not seem to understand this at all...HTT multiplies the FSB

So a stock 3200 939..will run at 200 with 5x HTT=1000
but so many people need to use a 3x HTT to be ok..but even at 300fsb this only 900

I am so confused???

and does HTT often lead to videocard instability??

 

[Dough1397]

htt multiplier is different than normal fsb multipliers... it usually is 3x 4x or 5x
general rule if the [fsb * htt multi] < 1000 mhz
to fidn your actual clock speed you must refer to the other multiplier and the fsb speed

 

[nealh]

well understand the how it mutliplies but what does it do..and why under 1000....is the difference between stock 5x htt x 200 on A64 much better than say 3x htt 260fsb=...780 vs 1000...hmm seems like a big difference


how does it affect performance ...is 4x htt * 260= 1040 bad.....will this cause videocard stuttering

 

[DrCool]

the new Athlon 64 architecture is unlike any other processor, and thus requires looking at things a little differently..

HTT (HyperTransport) is the new BUS architecture that AMD has been trying to work into it's systems for the past couple of years.. HTT is the bus on which ALL your components operate.. how the processor communicates with all the components on the motherboard. In the past, this bus was often the limiting factor in communications between the CPU, the Memory, the North / South bridges, and the graphics card.

A64 introduced more then one new way of thinking about CPU / Memory / and Motherboard architecture..
they also feature on core memory controllers..
the speed of communication between the CPU and the MEMORY is what was often referred to as FSB (200MHz / 266MHz / 333MHz / 400MHz), well that is no longer the case with the A64's, as the memory controller now opperates at core speed, just like the L2 cache.. the only difference is NO DDR memory exsists that can operate at core speed, so the memory must be run asynchonosly.. thus the lowest cpu:memory ratio possible with A64's is CPU:9 (ie 1800MHz core speed / 200MHz DDR Memory speed)

The HT 2x / 3x / 4x / 5x controls the speed at which the BUS operates, not at which the CPU/Memory operate.

I'm oversimplifying the whole affair, but someone may be able to post a link with a more through and detailed explaination.

5x HT = 1000MHz HyperTransport bus speed (ie 200MHz x HT setting)

HyperTransport offers such an increase in bus BANDWIDTH from previous BUS technology that there is no current performance benefit from running 3x HT (600MHz) vs 5x HT (1000Mhz)

 

[JBDan]

http://www.insanetek.com/index.php?page=overclocka64 This gives a little info as well

 

[Megatomic]

DrCool, what tasks might utilize more of the HTT bus bandwidth? I'm trying to figure out what problem AMD is trying to solve with the introduction of the HTT bus. If 3x200 is so much more than we need, why even tout 4x200 or more as is done already?

I currently have my system running at 5x200 HTT and you are right, I saw only a very minor increase in overall system performance. I wish, just for giggles, that I could do "something" with my computer that would use all the bandwidth available to it. Back in the day I remember when doing a CD to CD-R copy on the fly (not SCSI) would put a hurting on a computer. Nothing, aside from Prime95, does that to my computer now.

 

[nealh]

Thanks everyone makes more sense..


DR. Cool thank you ..very helpful

HTT bus of 3x 260 as my o/c is now is faster bandwidth than we can basically utilize which is why the stock 5x htt x 200 ...results in minimal/no singificanct performance differences...???

I realize I ignored the fact that my cpu o/ced is at 2600 and stock is at 2000.....