RDRAM (Rambus RAM) PC800

[Dark Ride]

I have 256 MB RDRAM (Rambus RAM) PC800, installed (2x128 MB).

The program "AIDA32" tells me that my RAM is running at 400 MHz :blink:

Shouldn't it run at 800 MHz , as it is PC800 RDRAM ???

EDIT:

Memory Module Properties

Module Name Samsung MR16R 1624AF0-CK8

Serial Number 3A84D604h

Module Size 128 MB (4 devices, 32 banks)

Module Type RIMM Module

Memory Type RDRAM

Memory Speed PC800 (400 MHz)

Module Width 16 bit

Module Voltage 2.5 V

Memory Module Features

HeatSpreader Present

Thermal Sensor Not Present

Memory Module Manufacturer

Company Name Samsung

Product Information http://www.samsung.com/Products/Semiconductor/DRAM/index.htm

Edited October 21, 2004 by Dark Ride

[TooPackShaker]

no its like ddr it hits the ram twice per clock cycle making the "effective" speed 800mhz

[Dark Ride]

no its like ddr it hits the ram twice per clock cycle making the "effective" speed 800mhz

584780778[/snapback]

Don't get it :huh: explain a little more

[UnrealFreak]

Instead of eating ONE KING sized MARSBAR a second,

You eat TWO NORMAL sized MARSBARs a second.

Therefore, because you're eating TWO normal sized ones - you are still eating the equivalent to a King Sized one in the same period time...

Hope that 'explains a little more' :)

[Dark Ride]

If I'm getting this right , that means:

If I would have 4 x 128 MB RDRAM , each module would be running at 200 Mhz ?

[TooPackShaker]

a mhz is a clock cycle

with sdram data is only transmitted once per clock cycle

ddr and rdram transmit data twice in one clock cycle

thats the best I understand it. you may want to google for an explanation of how ddr and rdram work if this isnt satisfactory

:edit: it has nothing to do with how many sticks you are running

when using ddr and rdram the effective speed is twice that of the actual operating speed when compared to regular sdram

[Spitfire_x86]

If I'm getting this right , that means:

If I would have 4 x 128 MB RDRAM , each module would be running at 200 Mhz ?

No, they would still run at 400 MHz.

The real speed is 400 MHz, but the effective speed is 2 x 400 MHz, since it carries two bit per cycle

[threetonesun]

If I'm getting this right , that means:

If I would have 4 x 128 MB RDRAM , each module would be running at 200 Mhz ?

584780893[/snapback]

No, DDR=double data rate. Double whatever the reported Mhz is for the effective.

[Dark Ride]

Ok, at least it's good to know that nothing is wrong with the memory :D

[Radium]

a mhz is a clock cycle

with sdram data is only transmitted once per clock cycle

ddr and rdram transmit data twice in one clock cycle

thats the best I understand it. you may want to google for an explanation of how ddr and rdram work if this isnt satisfactory

:edit: it has nothing to do with how many sticks you are running

when using ddr and rdram the effective speed is twice that of the actual operating speed when compared to regular sdram

Hz, Hertz is the number of cycles per second.

M = Mega, 10^6

One MHz is one million cycles per second.

And the clock signal changes state (high/low) two million times per second.

You have to include latency too. It's not zero-latency memory we're talking about.

[Dark Ride]

I know what Hertz are ;) I'm an electircian myself.I just don't get why it is running at 400 MHz :blink:

[UnrealFreak]

Perhaps you should try taking an IQ test... and tell us the result! (just joking)

As we said... DDR IS DOUBLE DATA RATE. PC800 is 400mhz... but it is RUN at twice the speed.

[Dark Ride]

Already did a test and my IQ is 122

the problem is that english isn't my native language, so I don't get everything you say :p

[Radium]

ah, many of us here on Neowin have that problem too, lacking words.

English is not my native language either. :)

The circuits triggers on both the raising and the falling edge of the clock.

You should know what a clock signal looks like. :)

Normally it only triggers on the raising edge when the signal goes from a low to a high state.

But RDRAM and DDR SDRAM triggers on the falling edge of the clock too, both from low to high and high to low.

http://www.corsairmemory.com/corsair/produ.../memory_basics/

It's a bit old now, but it's enough. :)

[Dark Ride]

Cool , thanks !!! :D