Question about Core 2 Duo FSB

I thought he was talking about how memory bandwidth is related to FSB and not how to calculate CPU speeds.

i.e. 200MHz memory (or DDR400) = PC3200 because it has a theoretical maximum memory bandwidth of 3200MB/s.

The multipliers you have listed are incorrect.
Wikipedia
 
yes i was refering to the bandwidth and not the multiplier.


So basically, the newer chips have a faster FSB which is multiplied by 4

2 physical cores and 2 logical cores each having their own system bus I assume.
 
The $6m Dan said:
I thought he was talking about how memory bandwidth is related to FSB and not how to calculate CPU speeds.

i.e. 200MHz memory (or DDR400) = PC3200 because it has a theoretical maximum memory bandwidth of 3200MB/s.

The multipliers you have listed are incorrect.
Wikipedia
Click to expand...


Mine are correct :confused: And the options I gave are also correct :confused:
 
but also you have to be careful because some DDR 2 ram even though branded at 6400 speed defaults to 5300, why I dont know but that certainly seems to be the case with my Asus DH mobo and Gskill 6400 nr ram
 
I am still very confused as to what RAM I should be buying when selecting DDR2 RAM for either an AMD AM2 or Intel Core 2 Duo system..

It's like on the older AMD CPUS it was like i said above ((FSB x 2) * bandwidith).. so ((200Mhz * 2) * 8) = 3200 meaning you would need a minimum of PC3200..

But I can't make out how this applies to the new CPUS and the bandwide like PC8000??


Please explain?
 
I just went for the OCuk bundle which was PC6400 memory. That would probably be your best bet?

Wiki says the following though-
Unlike the previous Pentium 4 and Pentium D design, the Core 2 technology sees a greater benefit from memory running synchronous with the Front Side Bus (FSB). This means that for the Conroe CPUs with FSB of 1066 MT/s, the ideal memory speed is PC2-4200. In some configurations, using PC2-5300 can actually decrease performance. Only when going to PC2-6400 is there a significant performance increase.
Click to expand...
 
put it anohter way... 266Mhz FSB * 4 = Memory 1064MHz effective yeah?

So with 1064MHz, which RAM do you buy? becuase going by the table below, it's none of them???

going by the method 1064 * 8 = fequency of 8512Mhz ???


or am i loosing the plot?
 
dont look at the 1066mhz bus speed, that AFTER it's quad pumped, look at it before its quad pumped, ie. 266mhz, thats the ACTUAL fsb of the cpu.

Table below shows what ram you shall need if you are NOT wanting to overclock your ram vs the fsb of the CPU

CPU FSB Ram
133mhz = pc2100
166mhz = pc2700
200mhz = pc3200
266mhz = pc4200
300mhz = pc4800
333mhz = pc5400
400mhz = pc6400
500mhz = pc8000

For example, you buy an e6600, standard fsb is 266mhz, so if you were not going to clock it, buy pc4200 ram, if you were going to clock it, buy the ram accoriding to the fsb u want to clock it to (so say u get the fsb to 400mhz, buy pc6400)

Now of course Ram will overclock too, so if you wanted to save money, you could clock the cpu to 400mhz fsb, and buy pc5400 ram (rated to 333mhz) and clock the ram to 400mhz.
 
gotcha yes - I was mislead by the 4 bit transfer speed.


((266 * 2) * 8) = 4256 PC4200

Thanks for clearing that up.


Pretty pointless buying PC8000 and beyond really ?
 
Intel quad pump, AMD only double pump, so there's the first difference.

So with intel, a 266mhz bus is 1066FSB, if you were running with a single channel memory config (just 1 module, or 2 but in the wrong slots), then you would indeed need 1066mhz memory to run 1:1.

However virtually (all?) motherboard for socket 775 have 128bit dual channel memory controllers, while the CPU socket is just 64 bits wide. Therefore, the memory is able to run at half the cpu's frequency and still maintain 1:1 performance.

So a Stock Core 2 processor, should be setup with 533Mhz PC4200. For overclocking faster memory is desirable.
 
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