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Re: RAM - so true. 2GB doesn't go as far as it used to.

I noticed something interesting on the M90 - the 4GB option (a mere $2200 add'l) has a slower RAM speed.

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Memory Capacities:
512MB to 2GB capacities available at 667MHz speed
4GB2 is available at 533MHz speed
Both speeds are 8.5 GB/s with dual-channel to help improve performance


Do you know why that is? I don't think I've ever seen a bus speed based on RAM quantity before this.

-Zeke


There are probably only two sockets for RAM modules, because that's likely all that the chipset is designed to drive without extra buffers + wait states.

To install 4GB therefore likely requires a pair of 2GB modules, each of which likely (current technology) simply has double the number of chips on them, compared with the 1GB modules.

Double the number of chips == double the bus load == slower rise/fall times on the signals == slower speed of operation to guarantee things still work. Alternatively, they could insert wait states everywhere and still use the faster clock, but that would be even slower if it were at all possible in the first place.

Cheers