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Discussion Starter · #1 ·
An amd64 say....newcastle 3000+ has an fsb of 200 right?

So total would be 4x200 = 800

running that with PC3200 ram would equate to fsb:mem speed (800:400)
hence a ratio (and a divider) of 2:1?

performance should be bottlenecked a fair bit with such a gap from a 1:1 ratio?

Is that all right or have i missed something about amds?
 

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Quote:


Originally Posted by mauguai

An amd64 say....newcastle 3000+ has an fsb of 200 right?

So total would be 4x200 = 800

running that with PC3200 ram would equate to fsb:mem speed (800:400)
hence a ratio (and a divider) of 2:1?

performance should be bottlenecked a fair bit with such a gap from a 1:1 ratio?

Is that all right or have i missed something about amds?

nope... the mem is running at full speed the x4 =800 is because of the cpu being quad pumped...
 

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Discussion Starter · #3 ·
Quote:


Originally Posted by spookedjunglist

nope... the mem is running at full speed the x4 =800 is because of the cpu being quad pumped...

nope as in there isn't anything i missed about amds or what?

no offence i found ur response a lil vague in answering my question(s)

I'm just wondering if there is much difference to having such a huge fsb compared to the mem speed which is only half.

I thought that 1:1 ratio was the optimum for any system

which makes me wonder when presscotts and amd64s with an fsb of 800 are coupled with PC3200 ram, how much potential performance is being missed out on due to the ram not being able to cater for a 1:1 ratio.

I know this applies to my system anyway which only has a cpu with an fsb of 400 anyway. so no problem reaching 1:1 there, once i got 1:1 with new PC3200 ram my framerates in hl2 jumped on average of 20+. The mem was PC2100 before.
 

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Quote:


Originally Posted by mauguai

nope as in there isn't anything i missed about amds or what?

no offence i found ur response a lil vague in answering my question(s)

I'm just wondering if there is much difference to having such a huge fsb compared to the mem speed which is only half.

I thought that 1:1 ratio was the optimum for any system

which makes me wonder when presscotts and amd64s with an fsb of 800 are coupled with PC3200 ram, how much potential performance is being missed out on due to the ram not being able to cater for a 1:1 ratio.

I know this applies to my system anyway which only has a cpu with an fsb of 400 anyway. so no problem reaching 1:1 there, once i got 1:1 with new PC3200 ram my framerates in hl2 jumped on average of 20+. The mem was PC2100 before.

Sorry being vague, Im at work and had to run and take care of something...
1:1 ratio is running your ram and CPU at the same FSB speed..
the CPU quad pumps the FSB so im not positive but i think that
the CPU sends 8bits per clock 4 on the rise and 4 on the fall of the clock
thats on a 800mhz FSB but your mobo only sees 200mhz
so 200mhz FSB coupled with 200mhz "pc3200ram" 1:1
thats about it... lemme know if this makes sense

lando has a better grip on the whole quad pumped thing if you ask him he might be a lil better at explaining it
 

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Because the memory controller is in the CPU core instead of the northbridge on Athlon 64s, bus speeds are determined in an almost completely different manner than most people are used to. Hyper-Transport essentialy replaces the external FSB in Athlon 64s, it's the 800MHz 16bit x 16bit bidrectional link between the processor and the system (chipset). It's base frequency is 200MHz as determined by the PLL (frequency generator) and inside the chipset is goes by a multiplier, x4 on socket 754, and x5 on Socket 939. The CPU clock speed is then determined by another multiplier by the original HTT/FSB base frequency of 200, so for a 3000 you have 200MHz HTT x 10 CPU multiplier = 2000MHz CPU clock speed. Now, the memory bus is not determined by the HTT base frequency, or at least not directly. Since the memory controller is on the CPU die, the memory bus is determined by an internal DIVIDER of the CPU frequency, which while running "1:1" would be the same as the CPU multiplier giving you 200MHz real, or 400Mhz effective, hence the need for PC3200/DDR400 RAM. So instead of running in a ratio with the FSB, the RAM is actually running at just a lower speed of the CPU clock. Technical speaking when overclocking the Athlon64s, you aren't changing the FSB, you're changing the HTT base frequency, which is why it's actually correct to say 200HTTx10 instead of 200FSBx10. Athlon 64s still have a Fronst Side bus (that being the link of the memory controller to the on die cache) but it is also directly integrated into the core and runs at the core CPU frequency and is 128 bits wide.
 

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Quote:


Originally Posted by YiffyGriffy

Because the memory controller is in the CPU core instead of the northbridge on Athlon 64s, bus speeds are determined in an almost completely different manner than most people are used to. Hyper-Transport essentialy replaces the external FSB in Athlon 64s, it's the 800MHz 16bit x 16bit bidrectional link between the processor and the system (chipset). It's base frequency is 200MHz as determined by the PLL (frequency generator) and inside the chipset is goes by a multiplier, x4 on socket 754, and x5 on Socket 939. The CPU clock speed is then determined by another multiplier by the original HTT/FSB base frequency of 200, so for a 3000 you have 200MHz HTT x 10 CPU multiplier = 2000MHz CPU clock speed. Now, the memory bus is not determined by the HTT base frequency, or at least not directly. Since the memory controller is on the CPU die, the memory bus is determined by an internal DIVIDER of the CPU frequency, which while running "1:1" would be the same as the CPU multiplier giving you 200MHz real, or 400Mhz effective, hence the need for PC3200/DDR400 RAM. So instead of running in a ratio with the FSB, the RAM is actually running at just a lower speed of the CPU clock.

*yawn* lol

sorry...tired

joking, nice one
 

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Discussion Starter · #7 ·
Quote:


Originally Posted by YiffyGriffy

Because the memory controller is in the CPU core instead of the northbridge on Athlon 64s, bus speeds are determined in an almost completely different manner than most people are used to. Hyper-Transport essentialy replaces the external FSB in Athlon 64s, it's the 800MHz 16bit x 16bit bidrectional link between the processor and the system (chipset). It's base frequency is 200MHz as determined by the PLL (frequency generator) and inside the chipset is goes by a multiplier, x4 on socket 754, and x5 on Socket 939. The CPU clock speed is then determined by another multiplier by the original HTT/FSB base frequency of 200, so for a 3000 you have 200MHz HTT x 10 CPU multiplier = 2000MHz CPU clock speed. Now, the memory bus is not determined by the HTT base frequency, or at least not directly. Since the memory controller is on the CPU die, the memory bus is determined by an internal DIVIDER of the CPU frequency, which while running "1:1" would be the same as the CPU multiplier giving you 200MHz real, or 400Mhz effective, hence the need for PC3200/DDR400 RAM. So instead of running in a ratio with the FSB, the RAM is actually running at just a lower speed of the CPU clock. Technical speaking when overclocking the Athlon64s, you aren't changing the FSB, you're changing the HTT base frequency, which is why it's actually correct to say 200HTTx10 instead of 200FSBx10. Athlon 64s still have a Fronst Side bus (that being the link of the memory controller to the on die cache) but it is also directly integrated into the core and runs at the core CPU frequency and is 128 bits wide.

Oh yeah forgot to take into account the on die memory controller...

Thanks this was the kinda indepth response i was after
I haven't a clue about amd64s
 

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Discussion Starter · #8 ·
This table bugging me now, it conflicts with what u said about cpu clock being determined from HTT x multiplier

Quote:


Originally Posted by YiffyGriffy

The CPU clock speed is then determined by another multiplier by the original HTT/FSB base frequency of 200, so for a 3000 you have 200MHz HTT x 10 CPU multiplier = 2000MHz CPU clock speed.

sorry bout attachment, insert image dont work
 

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As much as the table is interesting, I think Yiffy is correct 100%.

My reasoning is how can your HTT be 250MHz when your FSB is only 200MHz?

And for clarification, are you talking about a newcastle socket 939 or a newcastle socket 754? They make both.

My long time understanding of HTT for 754's and 939's is that the HTT Multiplier is 4 and 5 respectively.

All processors and ram, AMD and Intel alike, are based off of one thing...FSB.

FSB dictates clock speed, ram speed, HTT speed...You cannot set your HTT to be 250 while your FSB is 200. If you find a way, lemme know, I will stand corrected.
 

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Quote:


Originally Posted by Xavier1421

As much as the table is interesting, I think Yiffy is correct 100%.

My reasoning is how can your HTT be 250MHz when your FSB is only 200MHz?

And for clarification, are you talking about a newcastle socket 939 or a newcastle socket 754? They make both.

My long time understanding of HTT for 754's and 939's is that the HTT Multiplier is 4 and 5 respectively.

All processors and ram, AMD and Intel alike, are based off of one thing...FSB.

FSB dictates clock speed, ram speed, HTT speed...You cannot set your HTT to be 250 while your FSB is 200. If you find a way, lemme know, I will stand corrected.

I think the HTT must be 250 Xavier, otherwise whats the difference between the 3400 and 3500 chips?
 

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Discussion Starter · #11 ·
Quote:


Originally Posted by Xavier1421

As much as the table is interesting, I think Yiffy is correct 100%.

My reasoning is how can your HTT be 250MHz when your FSB is only 200MHz?

And for clarification, are you talking about a newcastle socket 939 or a newcastle socket 754? They make both.

My long time understanding of HTT for 754's and 939's is that the HTT Multiplier is 4 and 5 respectively.

All processors and ram, AMD and Intel alike, are based off of one thing...FSB.

FSB dictates clock speed, ram speed, HTT speed...You cannot set your HTT to be 250 while your FSB is 200. If you find a way, lemme know, I will stand corrected.

Well the reason i started this thread was to help my mate who just got a 3000+ newcastle on 754 and wanted to help him figure out if there were any bottlenecks or what parts could do with a bit more love.

The HTT thing on the 939 boards was brought up cos its doing my head in and cos i'll be getting a 939 in mid summer myself so might as well try to understand the inner workings.

After a lil searching I couldn't find anything that supports this 250 value aside from muffins point about it being the only difference between the 939 3400+ & 3500+...so uh...i dunno. I'd always thought of tomshardware.com to be a reliable source of info.
 

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That must be some sort of missprint or something. Socet 939s run 1GHz HTT frequency, but they do it by running a x5 multiplier on HTT instead of x4, so I have no idea what that means... might have to have a talk with Tom's Hardware. I've gotten a majority of the information I know from AMD's official technical documention so...
 
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