What fequency of RAM should a Pentium D at 3.4 use?

medeamajic

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Feb 6, 2003
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I have a Pentium D at 3.4 GHZ (945) with an 800 MHZ FSB. I bought 800 MHZ DDR2 RAM but the BIOS sees the CPU at 3.4 GHZ the RAM at 1 GB but the freqency is only 566. Did they sell me the wrong RAM? Should it be clocking in at 800 MHZ instead of 566?

Any info would help.
 

cme2c

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Jun 17, 2006
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I have a Pentium D at 3.4 GHZ (945) with an 800 MHZ FSB. I bought 800 MHZ DDR2 RAM but the BIOS sees the CPU at 3.4 GHZ the RAM at 1 GB but the freqency is only 566. Did they sell me the wrong RAM? Should it be clocking in at 800 MHZ instead of 566?

Any info would help.

Mine runs exactly the same. FSB=Front side bus This is actually 200MHz, "quad pumped", that is, the cpu can do 4 "things" per clock cycle hence 4X200=800 (this is an oversimplification, but bear with me...)

The memory is DDR2 (Dual Data Rate). The memory bus runs at 266 MHz, the memory can do 2 "things" per cycle hence 566. There is a 3:4 ratio between the FSB and memory bus. A free program called cpu-z can tell you all of this and more about your system.

Depending on your motherboard you may be able to speed up the ram, or tighten the timings by changing these settings. You may be able to set a 2:1 ratio, speding the memory bus to 400Mhz to fully use the 800Mhz memory. Good luck!!
 

medeamajic

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Feb 6, 2003
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I meant to post 533 not 566 for the RAM.

This is odd. My FSB is set a 200 so quad pumped it would be 800. I have 200 X 17 for the 3.400 GHX CPU speed. The RAM Speed can be set to 533, 667 and 800 MHZ. In my MOBO they want the actaul RAM speed like 800 MHZ for PC 6400 RAM not a mulitplier. When I make the change in the BIOS the MOBO shuts down. When it reboots it beeps and my PC goes blanc. No POST at all. I can reset the MOBO jumpers to default to get eveything back again but I am convivnced my RAM is only 533 MHZ. I think I was ripped of.
 

Mondoman

Splendid
You need to tell us the brand and model number of your components, including the RAM, the motherboard, the CPU heatsinkfan, the power supply and your graphics card at a minimum.

Download PC Wizard 2006 (free). Under the Hardware section, click on the Mainboard icon (green arrow pointing down to computer case), then double-click on "Chipset" in the list that appears in the upper right window. The bottom window will give a lot of info; print or write down the "Northbridge Information" and the "Memory Information".
Now, back in the upper right window, double-click on "Physical Memory", print or write down the info in the bottom window under the first "Information SPD EEPROM" section.

Also, download memtest86+ (self-booting, on either floppy or CD such as The Ultimate Boot CD) for later memory testing.