Installing a Fast Chip...

[DavidMil]

I know this has been kicked around before but:  Is it worth swapping out a C012399B for a fast chip in an old 800.  And does anyone have a

program that allows the two chips to run a stress test one after the other (I know that a power down and a physical swap of the two chips

would be needed between tests) so someone could compare the results?

 

Thank you,

DavidMil  

[Rybags]

It's just a 2K ROM - so it'll either work or not.  If your existing one was faulty you'd likely know it by now although non-Basic games in general don't tend to use the FP routines.

 

A bunch of Basic games would probably be sufficient to test it out.  Go for ones that have no or little usage of assembly routines.

 

There's various SysInfo type programs around - not sure which if any will checksum and identify it as a Fastchip.

But if you have means to get downloaded files onto your Atari it'd be an easy task to load the 2K image into Ram then compare it to what you have.

[DavidMil]

Here is some info that I found about the Fast Chip.  I never gave any thought about running the Computer faster with the ANTIC chip disabled.

I guess for running stress tests that would be the way to go.

 

David

 

[Rybags]

Given it's just a Rom and not a processor, stress test in my book would mean doing lots of memory accesses to it.

 

You could point the character set to $D800 which would mean plenty of accesses taking place.

Put some random characters onscreen then observe if any graphical glitching occurs.

[Faicuai]

6 hours ago, DavidMil said:

Is it worth swapping out a C012399B for a fast chip in an old 800.

If you are running SW that requires Floating-Point computations (whether written on Basic, Action, or apps like SynCalc), absolutely yes, and leave permanently installed (x2 to x3 speed improvements).

 

And if you even run your machine in a 80-col. environment like Bit3 (internal) or XEP80 (external), expect even higher performance gains (because DMA is not required for a typical E: interactive session on those environments).

 

If you are not running such titles, no major gain, then.

[1050]

Caution about any Newell offering containing the fast chip code, it might be broken at offset 0x01E0.

It should be E9h, instead you might find E5h as found in the OMNIMON XL ROM code. So in the OMNIMON code the offset is different due to the fast chip code being included inside a larger file - it's offset there is 0x19E0 representing +0x1800.

 

I dunno why it's broke or how it got broke, but I do know it might effect things. The proper code does a subtract from 09h and the broken code does a subtract of the value held at BOOT memory variable (0x0009) which is usually set to one. The end result will be different I would think.

[drac030]

13 minutes ago, 1050 said:

I do know it might effect things

It does not. The error is real, but that code is not used anywhere anyways.