will PC2-6400p work in my Mac Pro

Hi there :)

will PC2-6400p - ECC Reg Server Memory work in my Mac Pro?

I know Mac should have 6400F - but they are very expensive

Thank You for help

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RAM Type: PC6400 DDR2 ECC Min. RAM Speed: 800 MHz

Details: Uses "800 MHz DDR2 ECC fully-buffered DIMM (FB-DIMM) memory" and has a "256-bit wide memory architecture".

On the 2008 machine, I have found several machines with

RAM Type: PC5300 DDR2 ECC Min. RAM Speed: 667 MHz installed from the factory and gotten improved results with the 6400. EveryMac reports the 6400 as the correct RAM anyway.

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My question was about that one letter different - P or F

I've read somewhere - that with P (even if it has correct specification DDR2 800MHz and ECC but it is PC2-6400P <--------- P it has DIFFERENT physical pin hole cut - it it is impossible to stick into RAM slots in Mac Pro 2008 - BUT I do not know that 100% - just look for confirmation :)


DDR2-xxx denotes data transfer rate, and describes raw DDR chips, whereas PC2-xxxx denotes theoretical bandwidth (with the last two digits truncated), and is used to describe assembled DIMMs. Bandwidth is calculated by taking transfers per second and multiplying by eight. This is because DDR2 memory modules transfer data on a bus that is 64 data bits wide, and since a byte comprises 8 bits, this equates to 8 bytes of data per transfer.


In addition to bandwidth and capacity variants, modules can

Optionally implement ECC, which is an extra data byte lane used for correcting minor errors and detecting major errors for better reliability. Modules with ECC are identified by an additional ECC in their designation. PC2-4200 ECC is a PC2-4200 module with ECC. An additional P can be added at the end of the designation, P standing for parity (ex : PC2-5300P).

Be "registered" ("buffered"), which improves signal integrity (and hence potentially clock rates and physical slot capacity) by electrically buffering the signals at a cost of an extra clock of increased latency. Those modules are identified by an additional R in their designation, whereas non-registered (a.k.a. "unbuffered") RAM may be identified by an additional U in the designation. PC2-4200R is a registered PC2-4200 module, PC2-4200R ECC is the same module but with additional ECC.


But fully buffered modules, which are designated by F or FB and do not have the same notch position as other classes. Fully buffered modules cannot be used with motherboards that are made for registered modules, and the different notch position physically prevents their insertion.

Note: registered and un-buffered SDRAM generally cannot be mixed on the same channel.


so basically - if I got Mac Pro which normally has FB RAM modules - even if all of them removed - the only way to buy new one is.... to buy FBs? :)


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