A64 and RAM

[imported_Noob]

Is the FSB Speed of an A64 determined by the RAM speed? If so would it be worth getting some PC4400 RAM?

 

[ryanv12]

no don't bother with that high bandwidth ram. If you want performance, get low latency PC3200.

 

[imported_Noob]

Originally posted by: ryanv12
no don't bother with that high bandwidth ram. If you want performance, get low latency PC3200.

So would a S939 A64 run at a 2GHz FSB no matter what RAM the speed is?

 

[SirBrass]

question, how do they get away with an actual clock speed of 2 GHz? That clock would be emitting microwaves. I know actua processor clock pulses are psuedo pulses from a much slower clock using some sweet circuit trickery to produce multiple pulses that when combined add up to the processor speed, but that 'slower' clock is the FSB speed, right?

/me sort of remembers what he learned in his microprocessor class 😉

 

[n7]

Ahhhhh, i am not good explaining this, but here's a little info (to the experts: please correct me if i'm wrong):

You mentioned 2 GHz. That would be the speed of the HT (Hypertransport) not FSB.
A64's do not have a FSB; they have what's called HTT.

To get HT bus speed you have LDT*HTT*2 = HT bus speed
E.g on my system:
LDT @ 4x
HTT @ 240
= 960*2 = 1920 MHz HT bus

Now RAM normally runs the same speed as the HTT (200:200)

You can use a divider though; allows you to run the HTT higher than the RAM.

E.g. on my system:
Using 166 RAM divider aka 6:5, i run my HTT at 240, which puts the RAM at 200
I would recommend researching the subject, since i have major trouble explaining it simply.
I hope someone with better explanation skills can reiterate & make it more understandable...

 

[edmundoab]

having a high bandwidth ram does allow you to run the ram at 1:1 though,
although many says that it doesn't really put things into advantage and running a divider doesn't hurt its performance

im running a divider myself but just going as high as my RAM can take me at CAS 2 intact.