[gumby5647]

does anybody know of a website that has benchmarks on the older 68k chips.

im trying to find out how much faster a 25mhz 040 is over a 25mhz 030 etc....

Macspeedzone.com has what you're looking for (although I can't understand why).
http://macspeedzone.com/

Click on the "Old Macs" tab and then go to early 1995.

[superlarry]

if you're familiar with PC chips, the motorola 68030 -> 68040 is very similar to intel's move from 386 -> 486. there is an 8k cache embedded on the chip which speeds things up dramatically.
also, there is info at motorola's website:

68030: http://e-www.motorola.com/collateral/LIBMC68030.html
68040: http://e-www.motorola.com/collateral/LIBMC68040.html

[jeromep]

This is purely anicdotal, but the speed and performance improvement between the 030 and 040 is based more on the advances of chip integration and less an actual change in the archetecture. 030s never had a math co-processor or floating point unit embeded in it. The floating point system usually consisted of a Motorola 68882 math co-processor adjoining it on the motherboard. In the case of a full blown 040, the math co was on chip, like so many of our modern RISC processors and the Intel processors. The LC040 didn't have a math co, making it a much less desireable chip and today feels significantly more sluggish than a full 040 running at the same clock rate.

From my experience the IIfx, which had a 40Mhz 030 and a math co performed to a level aproximately equivelant to a Quadra 610 or possible 650. I still have a Quadra 950 in production for email and general AppleTalk serving. It is not the fastest or most efficient machine in the world, but it holds its own. I would not try the same tasks on a IIfx despite its beefieness.