HT multiplier question

[bluslice]

i'm OCing my rig:

240 (HTT)
10 (HTT multiplier)
166 (Memory Clock)
5x (HT multiplier)

I'm wondering if it matters at all if I use such a high HT multiplier because all I'm trying to do is keep the HT speed under what's specified by the mobo manufacturer right?

for the a8n-sli, it's 2000 MT/s which to me is just 2000MHz. So (240 x 5) = 1200 MHz. This is well under 2000 so using 5 as the HT multiplier should be ok?

 

[Screech]

No. the HTT x HTT multi has to be at 1000 or less. you will have to use 4x for the 240 HTT, I think.

 

[bluslice]

Originally posted by: screech
No. the HTT x HTT multi has to be at 1000 or less. you will have to use 4x for the 240 HTT, I think.

yeah, I was thinking that I should be using a multiplier to keep it under 1000. So now my new question is, why do i need to keep it under 1000? isn't 1000 just the fsb of the mobo itself? plz correct if i'm wrong.

 

[Screech]

From what little I know, there is no FSB per se, since the memory controller is on the chip, and the Hypertransport links that to the rest of the chip or something like that. This can only run at 1000 mhz or less. I'm not sure how the motherboard really comes into this.... :\ Hopefully one of those A64 geniuses will come along shortly to explain all of this :beer:

 

[ts3433]

The 2000 figure comes from the bus being bi-directional, so 240x5/1200HT is still above the stock 1000HT if you're computing it this way. If you're stable with that, you can keep it, but there's really no difference in performance going to a lower multiplier.

 

[bluslice]

ah ic, it's bi-directional. that explains a lot.

 

[ts3433]

Yeah--the number doubling is sort of like what is done to speed ratings of DDR memory, but not really.

 

[bluslice]

ehhh, a little different depending on what you're saying. the reason for doubling the memory in DDR is because DDR(double date rate) sends two bits of data per clock vs SD (single data) which sends 1 bit per clock (Not sure if it's bits but i know DDR sends twice as much data over one clock). showing 2000MT/s is actually 1000MT/s for sending then 1000MT/s for receiving over one bus. Thus it's bidirectional. So yes, it is the same if you're referring to the doubling of the rates but technically they are very different

 

[Doctorweir]

I'd stay as close to 1000 as possible...the HT connects the processor to the Northbridge (aka all other devices) so the faster the interface, the better
You use 4x240=960 and you should be perfectly ok...

 

[Doctorweir]

Btw: still testing or why the 166 memory clock? You should set "DDR333" in the BIOS to get a more suitable multiplier and get the max out of your nice memory (240 with the DDR333 divider gives you stock 200 memory clock again)

 

[bluslice]

setting it to "ddr333" in bios is the same as saying 166mhz(6:5 ratio) memory clock. I actually found this a little confusing at first when I was trying to figure out where the memory divider was in the a8n-sli bios.

DDR400 = 1:1 = 200
DDR333 = 6:5 = 166
DDR266 = 3:2 = 133
DDR200 = 2:1 = 100