DDR-SDRAM intercompatibility (speed)

[Daemon666]

I am planning on building a new PC, but as I am on a budget (I'm only a student :( ), I want to start with low-speed RAM, and then buy some better stuff later on.
I was wondering if you can mix speeds (like PC 2100 with PC 2700) ? if so, what would be the consequences on performance ? I plan on buying an Abit AT7-MAX2 (not too xpensive, but plenty of room for upgrade and overclocking ;) )
Thanx

[Wiggo]

Some motherboards don't like mixed memory but yes you can but memory speeds will only be as fast as your slowest stick. ;)
<center>:cheers:</center>

[SileNceR]

provided your FSB doesnt go over 133mhz (266mhz DDR, pc2100) then you should be right, if you want to overclock to 166mhz (333mhz DDR, pc2700) you'll have to remove any pc2100 sticks or hope that they are pretty good quality enough to take the higher speed (and its a fair difference)

- assuming AMD from here on since im not familiar with abit model numbers -

I wouldn't reccomend the Abit board, but rather an EPoX 8k3a+ or 8k5a2/3+ seeing as the problems Abit boards have been having with capacitors exploding etc (See slashdot - http://slashdot.org/articles/02/11/0....shtml?tid=137) and besides, Epox is the better brand anyway IMO :)

Also to note if you get an epox one, they are able to run the ram at 166mhz while the cpu is at 133 or 100mhz - while this may not increase performance much (the cpu clock is a bottleneck here) hypertransport means that you will get a small difference out of it being at these speeds, although if you have the PC2100 then you will have to opt to set this back to DDR@FSB or 133mhz so as to avoid system crashes.

[RDR]

Where I buy hardware there's almost no difference in price between PC2100 & 2700 - there's a jump for PC3200 though.

I wouldn't buy less than PC2700 right now - even if I was planning to run it at 133MHz