Not so huge penalty for large amount of RAM

[CougTek]

In contrast with the results posted in an article at Firingsquad, Lost Circuits found out that the performance penalty assosciated with larger-than-1GB of memory isn't as significant as previously reported.

The problem seems to lie with Photoshop more than anything else.

The reason for going through all these benchmarks and writing this article is not to point a finger at anybody. Rather, it is to dam spreading of wrong information caused by some software glitches or else, being typical only for one particular hardware configuration but which, by no means, can be generalized. In not a single instance did we incur any performance hit greater than 6%, and those can be accounted for by some stabilizing measures, that is, more relaxed timings on the chipset level.

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In the end, the take home message is that on a correctly configured high quality i875 / i865-based mainboard, there is no performance hit per se associated with increase in memory density or filling up all memory ranks.