Stupid RAM questions...

GeneralOreo

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Oct 18, 2007
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1- Is DDR3 'backwards compatible' with DDR2? Bascially, if I get a DDR3 motherboard can I use DDR2 RAM?

2- Same with speeds, if a motherboard supports a certain speed, and I buy RAM that's slower than the motherboard's memory standard, with the memory work w/o any compatibility or performance problem?

Thanks for any help.
 

KIAman

Diamond Member
Mar 7, 2001
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1. It all depends on the motherboard. If the motherboard specifies it can take DDR2 and DDR3, then yes. If not, then no.

2. Motherboards typically offer a wide range of speeds. Just remember that the speeds are different depending on DDR2 and DDR3. The only real compatability you would ever have to worry about is the default RAM voltage and timings. Typically, most ram nowadays will exceed a motherboard's default configs.
 

GeneralOreo

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Oct 18, 2007
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Cool, thanks.

Just one more queston, not RAM related but sort of like the second one in the OP... The X38 motherboards I'm looking at list the FSB speed as 1600/1333MHz, both faster than a Q6600... I'm guessing I can still use a Q6600 on this motherboard and those speeds are just the maximum?
 

KIAman

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Mar 7, 2001
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The motherboard FSB are typically quad (as in 4x) the FSB of the CPU.
The 1600/1333 support for the X38 is mainly talking in relation to DDR3 and the motherboard will run the cpu FSB out of sync with the motherboard FSB.

Q6600 will work fine in the X38 motherboard and it will run correctly at 1066 FSB until you decide to overclock it.
 

buzz12

Junior Member
Oct 21, 2007
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No! as said, if the motherboard needs DDR2 then you cannot use DDR3 and vise versa.
however, i think there are some motherboards that support both DDR3 and DDR2 but chances are their not many!
 

PCTC2

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Feb 18, 2007
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Yeah. DDR2 and DDR3 slots are different. only P35C boards support both (perhaps X38C boards when they come out). You can't fit DDR2 in DDR3 or vise versa

But the X38 chipset supports current Core 2's (1066 FSB and 1333 FSB) and future 1333 and 1600 FSB Core 2 (Penryn)
 

gingerstewart55

Senior member
Sep 12, 2007
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Originally posted by: PCTC2
Yeah. DDR2 and DDR3 slots are different. only P35C boards support both (perhaps X38C boards when they come out).

Actually, it's up to the manufacturer of either the P35 board or the X38 board if the board will support DDR2 and DDR3 on the same board. Foxconn already has one board out that does both.....but as with the P35 boards that do the same, the OC ability of the memory suffers by having slots for both memory types on the motherboard. Seems like trying to be a jack-of-all-trades in the memory arena makes the board a fair performer but poor overclocker for the memory. Same problem existed with motherboards that had slots for both DDR and DDR2 RAM on them.

Foxconn DDR2/DDR3 X38 motherboard