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Author Topic: A3640 V3.0 refuses to run speed test on SysInfo V3.24 ?!  (Read 8560 times)

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Offline CatHerder

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Re: A3640 V3.0 refuses to run speed test on SysInfo V3.24 ?!
« on: December 26, 2005, 01:49:48 PM »
Quote

nasty wrote:
Sorry to go abit off-topic here, but can someone explain  LC" or "EC to me?  My mate tryed to explain to me but it kind of went in one ear and out the other :lol:


Certainly.

The "LC" means LowCost (literally). It was a 68040 chip produced by Motorola to fit a cost niche that Apple wanted for their MacIntosh computers and that Commodore scooped up to be able to sell 4000's for $65 less. The 68LC040 includes an FPU but lacks a MMU. (Memory Management Unit) It actualy DOES include an FPU. (I listed a whack of 68LC040's on eBay earlier and included incorrect information: out of curiosity yesterday I went and read the specs from Motorola explaining the differences...) I used to know this 10 years ago and forgot...

The "EC" means EmbeddedController, and it lacks both the MMU and the FPU and includes some embedded instruction sets. It uses less power, it runs cooler, and it was cheaper to produce and to buy. (It was a really good choice for the average 3000 desktop user who didn't plan on running Sculpt4D or Lightwave etc.)

The difference between a XC68040RC and an XC68EC040RC is the EC is missing the FPU portion of the chip as well as the MMU. This is very similar to comparing a 68030 Amiga that lacks a 68882 to an Amiga that has a 68030 and a 68882 installed. (The 68882 is the FPU.)

Will your Amiga run slower with an LC chip? Absolutely not. Will it run slower if you use specific applications requiring, or benefitting from an FPU? NO. The only time you will notice ANY problems is if you intend to run Unix on your Amiga (an A3000UX for example because Unix requires a MMU). Other than that, there is no "bad thing" about having an LC chip in an Amiga.

If you want to do renderings, play Quake, or do other applications that are very math intensive, then you want to upgrade your 68EC040 to a 68040 chip. If you only use your Amiga to play games, to edit music, to paint pictures, to type letters, to  do 99% of everything available out there for a stock Amiga then you don't need to worry about having an EC chip.  

People that say the LC chip is not a "real" 68040 (when talking about them in relation to an Amiga) are just misinformed or confused is all. :-)

68040 - includes both CPU FPU and MMU
68LC040 - includes both CPU and FPU
68EC040 - includes only the CPU and some custom embedded controller routines

(This all can be misleading, because there were a few batch runs of Motorola 68LC040 that were full 68040 chips (they were stamped wrong), and there were a few batch runs of LC that were EC chips and there is no way to know without testing each chip yourself.) Sucks, but that's the way it is . :-)
[color=000099]CatHerder[/color][/i]
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Offline CatHerder

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Re: A3640 V3.0 refuses to run speed test on SysInfo V3.24 ?!
« Reply #1 on: December 26, 2005, 09:23:29 PM »
Piru, that's what I thought too (and thought I recalled). But I also recall being told by our Motorola rep and our Commodore rep that selling 4000's with LC chips would only be effected (slower) for people who were doing renderings or video editing or other math intensive operations. And then Motorola's website contradicts itself as well for the XC/RC040 chips.

So, I guess people should try to stick with 68040 (non LC non EC) to be sure. :-D
[color=000099]CatHerder[/color][/i]
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Offline CatHerder

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Re: A3640 V3.0 refuses to run speed test on SysInfo V3.24 ?!
« Reply #2 on: December 26, 2005, 09:33:26 PM »
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nasty wrote:
Thank you for taking the time to explain in detail, it now makes sence. I take it you cant get an LC or EC 060?


No, but you can get 68EC060 cpus that are not the same as 68060 cpus and you generally want to avoid them because they contain a different set of replacement instructions that most Amiga accelerators don't know how to use and they lack a MMU.

Also, if you see a 68040RC66A (or 75A) (the A being important) you should avoid it or try to replace it with a non "A" chip version. I don't recall specifically why, but I think it had something to do with a different set of instructions in the chip that the Amiga can't address.

Of course, like anything I discuss, I could be talking out my arse... but I'm pretty sure I'm fairly accurate on the above info. :lol:
[color=000099]CatHerder[/color][/i]
Go Graphical Website Design is what I do.
My eBay World <- Amiga swag, if any.