Quest for OC Knowledge

sniperchang

sniperchang

New Member
I'm trying to familirise my self with OCing. So far from what I read from OC 101 I understand this:

FSB is the core speed of CPU. Got that.

For the Socket 754, 939, 940 FSB also=Memory speed?

FSB X Multiplier = Net Speed. Got that.

I know the divider is for determining the mem speed. How do you get the divider? Is it the ratio thing?

No wait, FSB to RAM ratio determines the RAM speed.

:mad: Ok I don't know the divider part.

And HTT?? I though it was something with FSB, no?

And whats that other multiplier thing HT or something? :confused:

Someone clarefy please. :(
 
sniperchang said:
I'm trying to familirise my self with OCing. So far from what I read from OC 101 I understand this:

FSB is the core speed of CPU. Got that.

For the Socket 754, 939, 940 FSB also=Memory speed?

FSB X Multiplier = Net Speed. Got that.

I know the divider is for determining the mem speed. How do you get the divider? Is it the ratio thing?

No wait, FSB to RAM ratio determines the RAM speed.

:mad: Ok I don't know the divider part.



And HTT?? I though it was something with FSB, no?

And whats that other multiplier thing HT or something? :confused:

Someone clarefy please. :(
Click to expand...

The amd 64/x2/fx series dont have FSB, instead they have HTT, which is quite similar to FSB.
 
liuliuboy said:
The amd 64/x2/fx series dont have FSB, instead they have HTT, which is quite similar to FSB.
Click to expand...

So the HTT is the core speed, wich is also the memory speed, is that right? And for those with a FSB, explain the ratio/divider please. thanks
 
sniperchang said:
So the HTT is the core speed, wich is also the memory speed, is that right?
Click to expand...
not quite. this is the case if you do not have a divider in place. a divider, like you said, is a ratio. for example, if your htt is 200mhz with no divider, then your memory will run at 200mhz, or pc3200 speed. if you have a 4:3 multiplier in place, then that machine with 200htt will have it's memory at 150mhz, or pc2400 speed. hope this answers your question.
 
palmmann said:
not quite. this is the case if you do not have a divider in place. a divider, like you said, is a ratio. for example, if your htt is 200mhz with no divider, then your memory will run at 200mhz, or pc3200 speed. if you have a 4:3 multiplier in place, then that machine with 200htt will have it's memory at 150mhz, or pc2400 speed. hope this answers your question.
Click to expand...

Thanks, thats clears things up. So the CPUs with FSB, the memory has an idependent clockspeed, correct?
 
sniperchang said:
Unless a divider is put, right?
Click to expand...
When you set a divider, it loweres the stock speed to say, DDR333. But when you overclock it will still raise the memory speed. The higher the FSB, the lower the memory divider has to be.
 
So the HTT is the core speed, wich is also the memory speed, is that right?
Click to expand...
no htt is not the core clock speed but is based on a mutliple of the core clock which leads nicely too...
Ok, I understand, but whats a LDT multiplier?
Click to expand...
this is the multiplier between cor clock and htt.
 
just read cpu101 or overclocking 101...
htt = hypertransport. on 754 and 940 socket system this is two 16-bit bandwidths of 800mhz, and on 939 systems its two 16-bit bandwidths of 1000mhz or 1ghz.
LDT speed is the "core speed" you referred to.... or the 200mhz.
cpu speed is the LDT speed multiplied by the cpu multiplier.
memory speed is the LDT speed taking into account any memory dividers.
fsb (front side bussing) = hypertransport or HTT speed for AMD chips... which comes in two 16-bit bandwidths as i said... and is ultimately made up of a hypertransport multiplier, 5x for 939 4x for 940 and 754 sockets.
 
SLi WooDy said:
you dont nessercarly have to enter a different memory divide if your memory can run at the OCed fsb speed.
Click to expand...
Head... bang.... wall....bang.... head....bang....wall.....bang
 
fade2green514 said:
haha DUHH wow... most people's memory can't handle such speeds though... try to run ddr400 ram at ddr480??! no way mannn..
Click to expand...

my old OCZ DDR433 ran @ DDR520 just fine :D
 
fade2green514 said:
just read cpu101 or overclocking 101...
htt = hypertransport. on 754 and 940 socket system this is two 16-bit bandwidths of 800mhz, and on 939 systems its two 16-bit bandwidths of 1000mhz or 1ghz.
LDT speed is the "core speed" you referred to.... or the 200mhz.
cpu speed is the LDT speed multiplied by the cpu multiplier.
memory speed is the LDT speed taking into account any memory dividers.
fsb (front side bussing) = hypertransport or HTT speed for AMD chips... which comes in two 16-bit bandwidths as i said... and is ultimately made up of a hypertransport multiplier, 5x for 939 4x for 940 and 754 sockets.
Click to expand...

If I understand according to fade,

1.LDT is the correct name for the "base clock" before the mulitplier.
So LDT X Mulitplier = Net Speed of CPU
For My CPU as Exemple it's 200MHz X 10 = 2000MHz

2. Whats the HTT for? I understand that HTT (Mines at 200.0MHz to use as an example) X 5 for 939 sockets = 1000MHz. Whats this for/what does it do?
Is LDT related to the HTT any way, or they are just both set to 200MHz?

3. Net Speed of CPU/ Divider = memory speed. Exemple my CPU net speed is 2000MHz divider is 10 so 2000/10=200MHz

But now I read this
apj101 said:
no htt is not the core clock speed but is based on a mutliple of the core clock which leads nicely too...

this is the multiplier between cor clock and htt.
Click to expand...

Sound like Core Speed X LDT = HTT

Is there a correct name for Core Speed (since it can get mixed up with the Net Core Speed)

I think I need more clearafication. I read the 101's over and over, but it seems a little mixed up for me. Thanks for any replies.
 
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Memory runs at the speed of your FSB. If your FSB is at 200MHz, then your memory is at 200MHz. If you have a 4:3 divider, and your FSB is 200MHz, then your memory should run at 150Mhz. This is used so you can OC your CPU via the FSB to speeds that your memory would not be able to handle. For example, (just an example), you raise your FSB to 500Mhz, but your memory can only handle 300Mhz, use a 5:3 divider. Please correct me if I'm wrong.

Also, I'm not exactly sure how to implement a divider. Is it software? Or is it in the bios?
 
sniperchang said:
Is there a correct name for Core Speed (since it can get mixed up with the Net Core Speed)

I think I need more clearafication. I read the 101's over and over, but it seems a little mixed up for me. Thanks for any replies.
Click to expand...

core (center) speed, or base speed is the LDT speed, the one that people mix up with cpu operating frequency.
the motherboard determines this speed and that is why you overclock from the bios. the cpu then multiplies this speed and ultimately increases the performance of the entire computer, since it is a "central processing unit." it communicates between all of the parts of the computer, and does mathematical operations and such if need be.

HTT is just hypertransport. im not 100% sure what it busses, between which parts... but i know that as long as you stay above like 700mhz it doesn't effect the operation of most applications.

"cpu operating frequency" would be the correct term for net core speed... and technically LDT speed came to be referred to the "core" speed just because it was the speed everything else bases its own speed on... so it's not even referring to a specific "cpu core" or anything like that, its just the center speed... not really the speed of any object, or "core."

also, don't forget the cpu operating frequency isn't the actually speed of the cpu's core which completes processes, for instance my X2 at 2.4ghz is NOT really to be combined as 4.8ghz. in fact, it's not even two busses of 2.4ghz, that is unless you have two CPU's in one system rather than two core's on a cpu... and even then it's not going to be as effective as 4.8ghz would be :)

think of it this way:
you have one train that travels at a top speed of X. adding another core would be like adding another train... it won't get the people there in half the amount of time... it will simply be able to move twice the amount of people... or in the case of cpu core's, the core's will be able to complete a process, or do math in half the amount of time.
however, lets say that each train carries 20 people, but you only have 15 to carry... two trains won't help you in this case, just as two cores won't increase performance in such a case...
which is why they say dual core cpu's only really help you in "multithreaded" applications.
:)
 
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