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Ram guide

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  • Memory
  • Overclocking
  • RAM
Last response: in Memory
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March 3, 2006 1:16:04 PM

Hey,
I was wondering.
Does anything over DDR400 PC3200 force an overclocking of the FSB?
Like how does the ram work in relation to the FSB. Say in a P4 800FSB, the FSB is just a 200X4 then the Mem controller is the FSB (200) X 2? And let's say it's ddr433. Does that mean that the FSB has to now be set to 216 in order to use the ddr433, or is it an independent increase?
Thank You,
Dustin

More about : ram guide

March 3, 2006 5:31:05 PM

Quote:
Does that mean that the FSB has to now be set to 216 in order to use the ddr433, or is it an independent increase?


To take advantage of the DDR433, then yeah you'd have to set the clock speed at 216. But that would be considered overclocking. Same goes for the pentium 4 FSB's.

-mpjesse
March 3, 2006 5:43:58 PM

What about ddr2?

So in my understanding, everything that is over pc3200 requires overclocking of the FSB in order for it to be used?
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March 4, 2006 1:00:56 AM

Duster, it doesn't require increasing the FSB for it to be used, it requires increasing FSB to take advantage of the RAM to it's full capacity. You can have RAM run at 300MHz and FSB at 200MHz, but that is asynchronous and not recommended. Asynchronous hurts Intel Pentium 4 platforms more than it does AMD Athlon 64's due to the Integrated Memory Controller, but I still recommend keeping them the same. DDR2 works the same as DDR1 in the aspect of overclocking FSB to keep same FSB to RAM ratio. DDR1 and DDR2 only differ by DDR2 allowing higher frequencies at higher latencies, thus being alot better for overclocking if you can get somewhat decent timings on the DDR2.

~~Mad Mod Mike, pimpin' the world 1 rig at a time
March 4, 2006 1:55:55 AM

Quote:
You can have RAM run at 300MHz and FSB at 200MHz


How can that be done on an intel based system? I can see it on an AMD cause the FSB is basically independant of the memory subsystem. But the memory subsystem and front side bus on intel based systems are tied together.

Is there something i'm missing?

-mpjesse
March 4, 2006 2:45:28 AM

Quote:
You can have RAM run at 300MHz and FSB at 200MHz


How can that be done on an intel based system? I can see it on an AMD cause the FSB is basically independant of the memory subsystem. But the memory subsystem and front side bus on intel based systems are tied together.

Is there something i'm missing?

-mpjesse

Actually, AFAIK those are 2 independent bus's that are in correlation just as the HTT is to it's RAM Bus. Because the Memory Controller inside the Northbridge is just like the Memory Controller inside the die of an AMD64 CPU. The FSB from the CPU has to access the Northbridge which access's the Mem Controller which sends the data onto the Memory Bus. Also, on an A64, AFAIK, there is a correlation between HTT and RAM, they aren't as "Independent" as one may think.

The CPU on an AMD64 sends signals TO the RAM @ CPU Core Frequency IIRC. Meaning, if you have a 2.2GHz 3700+, that's the speed you're going TO the RAM at. Than, there is a direct link back @ RAM speed to the Memory Controller. Meaning, if you have 220MHz Memory, you're able to use the entire bandwidth that the memory offers, without being hindered by the 8GB/s Maximum that 1000MHz HTT is. This is why I say AMD going to DDR2 will be able to surpass Intel extravigantly, because the FSB @ 800MHz = 6.4GB/s, 1066MHz = 8.533GB/s and 1333MHz = approx. 10GB/s, whereas it can be unlimited on w/ an A64.

~~Mad Mod Mike, pimpin' the world 1 rig at a time
a b } Memory
a b K Overclocking
March 8, 2006 4:00:04 AM

No, PC3200 doesn't overclock the bus. PC3700 doesn't either. You're getting confused, RAM doesn't have a speed.

RAM does NOT have a speed.

That's right, RAM has no speed!

The rated speed of RAM is simply the highest speed the manufacturer guarantees it to run stable at. Nothing more. PC3200 can run at PC2700, PC2100, or even PC1600 speed. The chipset sets the RAM speed, not the RAM.
a b } Memory
a b K Overclocking
March 8, 2006 4:01:34 AM

d00d, you've missed the last 7 years of Intel chipsets!

The i815 could run the CPU at 133FSB and the RAM at 100. And memory dividers have been in place on all subsequent chipsets.
!