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I'm confused on what speed RAM should be used in different systems. I'm under the impression that PC3200 is the highest speed RAM that AMD systems support unless overclocked. What about Intel? Could someone clear things up for me?
Thanks
Teh processor does not determine ram speed.
The ram bus on the motherboard does.
Larry
"Have no fear of perfection -- you'll never reach it."
Salvadore Dali
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Yeah but AMD and Intel systems have different bus speeds. A64 mobos have at least 1000MHz FSB, but yet PC3200 RAM is still recommended.. why?
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"Currently the fastest JEDEC approved specification for DDR 1 is PC3200 or DDR 400 memory. Running memory faster than PC3200 will not help the performance of your machine unless you are overclocking the machine."
Is that referring to all DDR1 systems? If so, I'm guessing the only reason to buy higher clocked DDR1(like DDR600) is if your overclocking?
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"...AMD and Intel systems have different bus speeds. A64 mobos have at least 1000MHz FSB, but yet PC3200 RAM is still recommended.. why?"
I'm gonna do the best I can...are ya ready to get confused?
Intel systems still use the conventional Northbridge-Southbridge chipset w/FSB system. That means the CPU communicates with the Northbridge chip which contains the memory controller, & the memory controller in turn communicates with the RAM. The Northbridge also communicates with the Southbridge chip. On a modern P4 system, the FSB runs at 200MHz, but since Intel "quad pumps" the bus, it's referred to as 800MHz FSB.
AMD's A64 system doesn't have a FSB. The memory controller is built into the CPU itself & it runs at full processor speed...in other words, a 2.0GHz A64 communicates with the memory controller at 2000MHz. The RAM is connected to the CPU/memory controller by a dedicated memory bus with a default speed of 200MHz. There is no Northbridge/Southbridge chipset...the A64 board uses a single chip chipset which communicates with the CPU via the "HyperTransporT" bus. The HTT bus on the S939 A64 system runs at 1000MHz (DDR2000).
Does that help?
Hellz Yea!
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So in order for the system to be able to use RAM above PC3200, you'd have to overclock the "dedicated memory bus" you spoke of?
200MHz x 2 = 400Mhz, and PC3200 = 400MHz.. is that why PC3200 is the highest speed it can operate by default?
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For best performance, you should strive to run the CPU frequency & the memory frequency at the same speed.
What I left out when describing the A64 system is how you arrive at the HTT bus speed. It's the product of the CPU freq & the HTT multiplier. On a S939 system, the default CPU freq is 200MHz, the default multiplier is 5x, so the HTT bus is 1000MHz. The HTT bus doesn't tolerate overclocking very well, so if you wanna overclock the CPU, you'd have to lower the HTT multi to 4x, then you could raise the CPU freq to 250MHz. But if you want your RAM freq to match the CPU freq, you'd need PC4000 (DDR500).
Hellz Yea!
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Is overclocking the RAM worth it? I heard the latency goes up, and it's not really worth it.
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